diff --git a/OpenAI-DotNet-Tests/TestFixture_03_Chat.cs b/OpenAI-DotNet-Tests/TestFixture_03_Chat.cs
index fe2021b6..d588763a 100644
--- a/OpenAI-DotNet-Tests/TestFixture_03_Chat.cs
+++ b/OpenAI-DotNet-Tests/TestFixture_03_Chat.cs
@@ -1,8 +1,11 @@
 using NUnit.Framework;
 using OpenAI.Chat;
+using OpenAI.Tests.Weather;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text.Json;
+using System.Text.Json.Nodes;
 using System.Threading.Tasks;
 
 namespace OpenAI.Tests
@@ -95,5 +98,90 @@ public async Task Test_3_GetChatStreamingCompletionEnumerableAsync()
                 }
             }
         }
+
+        [Test]
+        public async Task Test_4_GetChatFunctionCompletion()
+        {
+            Assert.IsNotNull(OpenAIClient.ChatEndpoint);
+            var messages = new List<Message>
+            {
+                new Message(Role.System, "You are a helpful weather assistant."),
+                new Message(Role.User, "What's the weather like today?"),
+            };
+
+            foreach (var message in messages)
+            {
+                Console.WriteLine($"{message.Role}: {message.Content}");
+            }
+
+            var functions = new List<Function>
+            {
+                new Function(
+                    nameof(WeatherService.GetCurrentWeather),
+                    "Get the current weather in a given location",
+                     new JsonObject
+                     {
+                         ["type"] = "object",
+                         ["properties"] = new JsonObject
+                         {
+                             ["location"] = new JsonObject
+                             {
+                                 ["type"] = "string",
+                                 ["description"] = "The city and state, e.g. San Francisco, CA"
+                             },
+                             ["unit"] = new JsonObject
+                             {
+                                 ["type"] = "string",
+                                 ["enum"] = new JsonArray {"celsius", "fahrenheit"}
+                             }
+                         },
+                         ["required"] = new JsonArray { "location", "unit" }
+                     })
+            };
+
+            var chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+            var result = await OpenAIClient.ChatEndpoint.GetCompletionAsync(chatRequest);
+            Assert.IsNotNull(result);
+            Assert.IsNotNull(result.Choices);
+            Assert.IsTrue(result.Choices.Count == 1);
+            messages.Add(result.FirstChoice.Message);
+
+            Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Content} | Finish Reason: {result.FirstChoice.FinishReason}");
+
+            var locationMessage = new Message(Role.User, "I'm in Glasgow, Scotland");
+            messages.Add(locationMessage);
+            Console.WriteLine($"{locationMessage.Role}: {locationMessage.Content}");
+            chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+            result = await OpenAIClient.ChatEndpoint.GetCompletionAsync(chatRequest);
+
+            Assert.IsNotNull(result);
+            Assert.IsNotNull(result.Choices);
+            Assert.IsTrue(result.Choices.Count == 1);
+            messages.Add(result.FirstChoice.Message);
+
+            if (!string.IsNullOrWhiteSpace(result.FirstChoice.Message.Content))
+            {
+                Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Content} | Finish Reason: {result.FirstChoice.FinishReason}");
+
+                var unitMessage = new Message(Role.User, "celsius");
+                messages.Add(unitMessage);
+                Console.WriteLine($"{unitMessage.Role}: {unitMessage.Content}");
+                chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+                result = await OpenAIClient.ChatEndpoint.GetCompletionAsync(chatRequest);
+                Assert.IsNotNull(result);
+                Assert.IsNotNull(result.Choices);
+                Assert.IsTrue(result.Choices.Count == 1);
+            }
+
+            Assert.IsTrue(result.FirstChoice.FinishReason == "function_call");
+            Assert.IsTrue(result.FirstChoice.Message.Function.Name == nameof(WeatherService.GetCurrentWeather));
+            Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Function.Name} | Finish Reason: {result.FirstChoice.FinishReason}");
+            Console.WriteLine($"{result.FirstChoice.Message.Function.Arguments}");
+            var functionArgs = JsonSerializer.Deserialize<WeatherArgs>(result.FirstChoice.Message.Function.Arguments.ToString());
+            var functionResult = WeatherService.GetCurrentWeather(functionArgs);
+            Assert.IsNotNull(functionResult);
+            messages.Add(new Message(Role.Function, functionResult));
+            Console.WriteLine($"{Role.Function}: {functionResult}");
+        }
     }
 }
\ No newline at end of file
diff --git a/OpenAI-DotNet-Tests/TestServices/WeatherService.cs b/OpenAI-DotNet-Tests/TestServices/WeatherService.cs
new file mode 100644
index 00000000..4158e4cd
--- /dev/null
+++ b/OpenAI-DotNet-Tests/TestServices/WeatherService.cs
@@ -0,0 +1,23 @@
+using System.Text.Json.Serialization;
+
+namespace OpenAI.Tests.Weather
+{
+    internal class WeatherService
+    {
+        public static string GetCurrentWeather(WeatherArgs weatherArgs)
+        {
+            return $"The current weather in {weatherArgs.Location} is 20 {weatherArgs.Unit}";
+        }
+    }
+
+    internal class WeatherArgs
+    {
+        [JsonPropertyName("location")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string Location { get; set; }
+
+        [JsonPropertyName("unit")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string Unit { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/OpenAI-DotNet/Chat/ChatRequest.cs b/OpenAI-DotNet/Chat/ChatRequest.cs
index 043e958f..e662830c 100644
--- a/OpenAI-DotNet/Chat/ChatRequest.cs
+++ b/OpenAI-DotNet/Chat/ChatRequest.cs
@@ -14,8 +14,8 @@ public sealed class ChatRequest
         /// The list of messages for the current chat session.
         /// </param>
         /// <param name="model">
-        /// ID of the model to use.<br/>
-        /// Currently, only gpt-4, gpt-3.5-turbo and gpt-3.5-turbo-0301 are supported.
+        /// Id of the model to use.<br/>
+        /// Currently, only gpt-4 and gpt-3.5-turbo and their variants are supported.
         /// </param>
         /// <param name="temperature">
         /// What sampling temperature to use, between 0 and 2.
@@ -66,6 +66,12 @@ public sealed class ChatRequest
         /// <param name="user">
         /// A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse.
         /// </param>
+        /// <param name="functionCall">
+        /// If functions is not null or empty, this is required.  Pass "auto" to let the API decide, "none" if none are to be called, or {"name": "function-name"}
+        /// </param>
+        /// <param name="functions">
+        /// An optional list of functions to get arguments for.
+        /// </param>
         public ChatRequest(
             IEnumerable<Message> messages,
             string model = null,
@@ -76,8 +82,10 @@ public ChatRequest(
             int? maxTokens = null,
             double? presencePenalty = null,
             double? frequencyPenalty = null,
-            Dictionary<string, double> logitBias = null,
-            string user = null)
+            IReadOnlyDictionary<string, double> logitBias = null,
+            string user = null,
+            string functionCall = null,
+            IEnumerable<Function> functions = null)
         {
             Model = string.IsNullOrWhiteSpace(model) ? Models.Model.GPT3_5_Turbo : model;
 
@@ -103,6 +111,14 @@ public ChatRequest(
             FrequencyPenalty = frequencyPenalty;
             LogitBias = logitBias;
             User = user;
+
+            if (string.IsNullOrEmpty(functionCall) && Functions is { Count: > 0 })
+            {
+                throw new ArgumentException("If functions are provided, please also provide a function_call specifier e.g. (auto, none, or {\"name\": \"<insert-function-name>\"})");
+            }
+
+            FunctionCall = functionCall;
+            Functions = functions?.ToList();
         }
 
         /// <summary>
@@ -200,5 +216,19 @@ public ChatRequest(
         /// </summary>
         [JsonPropertyName("user")]
         public string User { get; }
+
+        /// <summary>
+        /// If functions is not null or empty, this is required.  Pass "auto" to let the API decide, "none" if none are to be called, or {"name": "function-name"}
+        /// </summary>
+        [JsonPropertyName("function_call")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string FunctionCall { get; }
+
+        /// <summary>
+        /// An optional list of functions to get arguments for.
+        /// </summary>
+        [JsonPropertyName("functions")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public IReadOnlyList<Function> Functions { get; }
     }
 }
diff --git a/OpenAI-DotNet/Chat/Choice.cs b/OpenAI-DotNet/Chat/Choice.cs
index 840e8f17..38e99bc8 100644
--- a/OpenAI-DotNet/Chat/Choice.cs
+++ b/OpenAI-DotNet/Chat/Choice.cs
@@ -21,10 +21,12 @@ public Choice(
 
         [JsonInclude]
         [JsonPropertyName("message")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
         public Message Message { get; private set; }
 
         [JsonInclude]
         [JsonPropertyName("delta")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
         public Delta Delta { get; private set; }
 
         [JsonInclude]
diff --git a/OpenAI-DotNet/Chat/Function.cs b/OpenAI-DotNet/Chat/Function.cs
new file mode 100644
index 00000000..d79b4fe1
--- /dev/null
+++ b/OpenAI-DotNet/Chat/Function.cs
@@ -0,0 +1,81 @@
+using System;
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+
+namespace OpenAI.Chat
+{
+    /// <summary>
+    /// <see href="https://platform.openai.com/docs/guides/gpt/function-calling"/>
+    /// </summary>
+    public class Function
+    {
+        /// <summary>
+        /// Creates a new function description to insert into a chat conversation.
+        /// </summary>
+        /// <param name="name">
+        /// Required. The name of the function to generate arguments for based on the context in a message.<br/>
+        /// May contain a-z, A-Z, 0-9, underscores and dashes, with a maximum length of 64 characters. Recommended to not begin with a number or a dash.
+        /// </param>
+        /// <param name="description">
+        /// An optional description of the function, used by the API to determine if it is useful to include in the response.
+        /// </param>
+        /// <param name="parameters">
+        /// An optional JSON object describing the parameters of the function that the model should generate in JSON schema format (json-schema.org).
+        /// </param>
+        /// <param name="arguments">
+        /// The arguments to use when calling the function.
+        /// </param>
+        public Function(string name, string description = null, JsonNode parameters = null, JsonNode arguments = null)
+        {
+            if (string.IsNullOrWhiteSpace(name))
+            {
+                throw new ArgumentException($"{nameof(name)} cannot be null or whitespace.", nameof(name));
+            }
+
+            if (name.Length > 64)
+            {
+                throw new ArgumentException($"{nameof(name)} cannot be longer than 64 characters.", nameof(name));
+            }
+
+            Name = name;
+            Description = description;
+            Parameters = parameters;
+            Arguments = arguments;
+        }
+
+        /// <summary>
+        /// The name of the function to generate arguments for.<br/>
+        /// May contain a-z, A-Z, 0-9, and underscores and dashes, with a maximum length of 64 characters.
+        /// Recommended to not begin with a number or a dash.
+        /// </summary>
+        [JsonInclude]
+        [JsonPropertyName("name")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string Name { get; private set; }
+
+        /// <summary>
+        /// The optional description of the function.
+        /// </summary>
+        [JsonInclude]
+        [JsonPropertyName("description")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string Description { get; private set; }
+
+        /// <summary>
+        /// The optional parameters of the function.
+        /// Describe the parameters that the model should generate in JSON schema format (json-schema.org).
+        /// </summary>
+        [JsonInclude]
+        [JsonPropertyName("parameters")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public JsonNode Parameters { get; private set; }
+
+        /// <summary>
+        /// The arguments to use when calling the function.
+        /// </summary>
+        [JsonInclude]
+        [JsonPropertyName("arguments")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public JsonNode Arguments { get; private set; }
+    }
+}
diff --git a/OpenAI-DotNet/Chat/Message.cs b/OpenAI-DotNet/Chat/Message.cs
index 87210aed..8a224d01 100644
--- a/OpenAI-DotNet/Chat/Message.cs
+++ b/OpenAI-DotNet/Chat/Message.cs
@@ -17,11 +17,15 @@ public sealed class Message
         /// Optional, The name of the author of this message.<br/>
         /// May contain a-z, A-Z, 0-9, and underscores, with a maximum length of 64 characters.
         /// </param>
-        public Message(Role role, string content, string name = null)
+        /// <param name="function">
+        /// The function that should be called, as generated by the model.
+        /// </param>
+        public Message(Role role, string content, string name = null, Function function = null)
         {
             Role = role;
             Content = content;
             Name = name;
+            Function = function;
         }
 
         /// <summary>
@@ -36,14 +40,24 @@ public Message(Role role, string content, string name = null)
         /// </summary>
         [JsonInclude]
         [JsonPropertyName("content")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
         public string Content { get; private set; }
 
+        /// <summary>
+        /// The function that should be called, as generated by the model.
+        /// </summary>
+        [JsonInclude]
+        [JsonPropertyName("function_call")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public Function Function { get; private set; }
+
         /// <summary>
         /// Optional, The name of the author of this message.<br/>
         /// May contain a-z, A-Z, 0-9, and underscores, with a maximum length of 64 characters.
         /// </summary>
         [JsonInclude]
         [JsonPropertyName("name")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
         public string Name { get; private set; }
 
         public override string ToString() => Content ?? string.Empty;
diff --git a/OpenAI-DotNet/Chat/Role.cs b/OpenAI-DotNet/Chat/Role.cs
index 5a903871..6d543c4c 100644
--- a/OpenAI-DotNet/Chat/Role.cs
+++ b/OpenAI-DotNet/Chat/Role.cs
@@ -10,5 +10,7 @@ public enum Role
         Assistant = 2,
         [EnumMember(Value = "user")]
         User = 3,
+        [EnumMember(Value = "function")]
+        Function = 4,
     }
 }
\ No newline at end of file
diff --git a/OpenAI-DotNet/Embeddings/EmbeddingsRequest.cs b/OpenAI-DotNet/Embeddings/EmbeddingsRequest.cs
index eb75fc0d..b916fa2a 100644
--- a/OpenAI-DotNet/Embeddings/EmbeddingsRequest.cs
+++ b/OpenAI-DotNet/Embeddings/EmbeddingsRequest.cs
@@ -17,7 +17,7 @@ public sealed class EmbeddingsRequest
         /// Each input must not exceed 8192 tokens in length.
         /// </param>
         /// <param name="model">
-        /// ID of the model to use.<br>
+        /// ID of the model to use.<br/>
         /// Defaults to: <see cref="Model.Embedding_Ada_002"/>
         /// </param>
         /// <param name="user">
diff --git a/OpenAI-DotNet/Models/Model.cs b/OpenAI-DotNet/Models/Model.cs
index 43b3a2e8..20f6300e 100644
--- a/OpenAI-DotNet/Models/Model.cs
+++ b/OpenAI-DotNet/Models/Model.cs
@@ -72,12 +72,14 @@ public Model(string id, string ownedBy = null)
         public string Parent { get; private set; }
 
         /// <summary>
-        /// More capable than any GPT-3.5 model, able to do more complex tasks, and optimized for chat. Will be updated with our latest model iteration.
+        /// More capable than any GPT-3.5 model, able to do more complex tasks, and optimized for chat.
+        /// Will be updated with our latest model iteration.
         /// </summary>
         public static Model GPT4 { get; } = new("gpt-4", "openai");
 
         /// <summary>
-        /// Same capabilities as the base gpt-4 mode but with 4x the context length. Will be updated with our latest model iteration.
+        /// Same capabilities as the base gpt-4 mode but with 4x the context length.
+        /// Will be updated with our latest model iteration.  Tokens are 2x the price of gpt-4.
         /// </summary>
         public static Model GPT4_32K { get; } = new("gpt-4-32k", "openai");
 
@@ -87,6 +89,12 @@ public Model(string id, string ownedBy = null)
         /// </summary>
         public static Model GPT3_5_Turbo { get; } = new("gpt-3.5-turbo", "openai");
 
+        /// <summary>
+        /// Same capabilities as the base gpt-3.5-turbo mode but with 4x the context length.
+        /// Tokens are 2x the price of gpt-3.5-turbo. Will be updated with our latest model iteration.
+        /// </summary>
+        public static Model GPT3_5_Turbo_16K { get; } = new("gpt-3.5-turbo-16k", "openai");
+
         /// <summary>
         /// The most powerful, largest engine available, although the speed is quite slow.<para/>
         /// Good at: Complex intent, cause and effect, summarization for audience
diff --git a/OpenAI-DotNet/OpenAI-DotNet.csproj b/OpenAI-DotNet/OpenAI-DotNet.csproj
index 268dd919..6dc8837b 100644
--- a/OpenAI-DotNet/OpenAI-DotNet.csproj
+++ b/OpenAI-DotNet/OpenAI-DotNet.csproj
@@ -17,8 +17,10 @@ More context [on Roger Pincombe's blog](https://rogerpincombe.com/openai-dotnet-
     <RepositoryUrl>https://github.com/RageAgainstThePixel/OpenAI-DotNet</RepositoryUrl>
     <PackageTags>OpenAI, AI, ML, API, gpt-4, gpt-3.5-tubo, gpt-3, chatGPT, chat-gpt, gpt-2, gpt</PackageTags>
     <Title>OpenAI API</Title>
-    <Version>6.8.7</Version>
-    <PackageReleaseNotes>Version 6.8.7
+    <Version>7.0.0</Version>
+    <PackageReleaseNotes>Version 7.0.0
+- Added function calling to chat models
+Version 6.8.7
 - Added ToString and string operator to Moderation Scores
 Version 6.8.6
 - Populated finish reason in streaming chat final message content
diff --git a/README.md b/README.md
index 8845d4b4..0a42787f 100644
--- a/README.md
+++ b/README.md
@@ -39,8 +39,8 @@ Install-Package OpenAI-DotNet
 
 - [Authentication](#authentication)
 - [Azure OpenAI](#azure-openai)
-  - [Azure Active Directory Authentication](#azure-active-directory-authentication) :new:
-- [OpenAI API Proxy](#openai-api-proxy) :new:
+  - [Azure Active Directory Authentication](#azure-active-directory-authentication)
+- [OpenAI API Proxy](#openai-api-proxy)
 - [Models](#models)
   - [List Models](#list-models)
   - [Retrieve Models](#retrieve-model)
@@ -50,6 +50,7 @@ Install-Package OpenAI-DotNet
 - [Chat](#chat)
   - [Chat Completions](#chat-completions)
   - [Streaming](#chat-streaming)
+  - [Functions](#chat-functions) :new:
 - [Edits](#edits)
   - [Create Edit](#create-edit)
 - [Embeddings](#embeddings)
@@ -424,6 +425,90 @@ await foreach (var result in api.ChatEndpoint.StreamCompletionEnumerableAsync(ch
 }
 ```
 
+##### [Chat Functions](https://platform.openai.com/docs/api-reference/chat/create#chat/create-functions)
+
+> Only available with the latest 0613 model series!
+
+```csharp
+var api = new OpenAIClient();
+var messages = new List<Message>
+{
+    new Message(Role.System, "You are a helpful weather assistant."),
+    new Message(Role.User, "What's the weather like today?"),
+};
+
+foreach (var message in messages)
+{
+    Console.WriteLine($"{message.Role}: {message.Content}");
+}
+
+// Define the functions that the assistant is able to use:
+var functions = new List<Function>
+{
+    new Function(
+        nameof(WeatherService.GetCurrentWeather),
+        "Get the current weather in a given location",
+            new JObject
+            {
+                ["type"] = "object",
+                ["properties"] = new JObject
+                {
+                    ["location"] = new JObject
+                    {
+                        ["type"] = "string",
+                        ["description"] = "The city and state, e.g. San Francisco, CA"
+                    },
+                    ["unit"] = new JObject
+                    {
+                        ["type"] = "string",
+                        ["enum"] = new JArray {"celsius", "fahrenheit"}
+                    }
+                },
+                ["required"] = new JArray { "location", "unit" }
+            })
+};
+
+var chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+var result = await api.ChatEndpoint.GetCompletionAsync(chatRequest);
+messages.Add(result.FirstChoice.Message);
+Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Content} | Finish Reason: {result.FirstChoice.FinishReason}");
+var locationMessage = new Message(Role.User, "I'm in Glasgow, Scotland");
+messages.Add(locationMessage);
+Console.WriteLine($"{locationMessage.Role}: {locationMessage.Content}");
+chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+result = await api.ChatEndpoint.GetCompletionAsync(chatRequest);
+messages.Add(result.FirstChoice.Message);
+
+if (!string.IsNullOrWhiteSpace(result.FirstChoice.Message.Content))
+{
+    // It's possible that the assistant will also ask you which units you want the temperature in.
+    Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Content} | Finish Reason: {result.FirstChoice.FinishReason}");
+
+    var unitMessage = new Message(Role.User, "celsius");
+    messages.Add(unitMessage);
+    Console.WriteLine($"{unitMessage.Role}: {unitMessage.Content}");
+    chatRequest = new ChatRequest(messages, functions: functions, functionCall: "auto", model: "gpt-3.5-turbo-0613");
+    result = await api.ChatEndpoint.GetCompletionAsync(chatRequest);
+}
+
+Console.WriteLine($"{result.FirstChoice.Message.Role}: {result.FirstChoice.Message.Function.Name} | Finish Reason: {result.FirstChoice.FinishReason}");
+Console.WriteLine($"{result.FirstChoice.Message.Function.Arguments}");
+var functionArgs = JsonConvert.DeserializeObject<WeatherArgs>(result.FirstChoice.Message.Function.Arguments.ToString());
+var functionResult = WeatherService.GetCurrentWeather(functionArgs);
+messages.Add(new Message(Role.Function, functionResult));
+Console.WriteLine($"{Role.Function}: {functionResult}");
+// System: You are a helpful weather assistant.
+// User: What's the weather like today?
+// Assistant: Sure, may I know your current location? | Finish Reason: stop
+// User: I'm in Glasgow, Scotland
+// Assistant: GetCurrentWeather | Finish Reason: function_call
+// {
+//   "location": "Glasgow, Scotland",
+//   "unit": "celsius"
+// }
+// Function: The current weather in Glasgow, Scotland is 20 celsius
+```
+
 ### [Edits](https://platform.openai.com/docs/api-reference/edits)
 
 Given a prompt and an instruction, the model will return an edited version of the prompt.