diff --git a/api-core/build.gradle b/api-core/build.gradle
index 3b5d6ea78..cc3a4ca35 100644
--- a/api-core/build.gradle
+++ b/api-core/build.gradle
@@ -22,6 +22,8 @@ dependencies {
     // Okio used by Moshi
     implementation "com.squareup.okio:okio:$okioVersion"
 
+    // Test dependencies
+    testImplementation "junit:junit:$junitVersion"
 }
 
 compileKotlin {
diff --git a/api-core/src/main/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptor.kt b/api-core/src/main/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptor.kt
index 12f2eb3f8..4e6188a1d 100644
--- a/api-core/src/main/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptor.kt
+++ b/api-core/src/main/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptor.kt
@@ -32,8 +32,11 @@ import okhttp3.Response
  * @param userAgent The user agent that should be sent with every request.
  */
 class UserAgentHeaderInterceptor(private val userAgent: String) : Interceptor {
-    override fun intercept(chain: Interceptor.Chain): Response =
-        chain.proceed(chain.request().newBuilder().header(HEADER_USER_AGENT, userAgent).build())
+    override fun intercept(chain: Interceptor.Chain): Response = chain.proceed(chain.request().let { request ->
+        val updatedHeaders = request.headers().newBuilder().addUnsafeNonAscii(HEADER_USER_AGENT, userAgent).build()
+
+        request.newBuilder().headers(updatedHeaders).build()
+    })
 
     companion object {
         private const val HEADER_USER_AGENT = "User-Agent"
diff --git a/api-core/src/test/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptorTest.kt b/api-core/src/test/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptorTest.kt
new file mode 100644
index 000000000..9daa66f2d
--- /dev/null
+++ b/api-core/src/test/java/com/vimeo/networking2/internal/interceptor/UserAgentHeaderInterceptorTest.kt
@@ -0,0 +1,57 @@
+package com.vimeo.networking2.internal.interceptor
+
+import okhttp3.Call
+import okhttp3.Connection
+import okhttp3.Interceptor
+import okhttp3.Protocol
+import okhttp3.Request
+import okhttp3.Response
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import java.util.concurrent.TimeUnit
+
+class UserAgentHeaderInterceptorTest {
+
+    private fun createChain(): Interceptor.Chain = object : Interceptor.Chain {
+        override fun request(): Request = Request.Builder().url("https://vimeo.com").build()
+
+        override fun proceed(request: Request): Response = Response.Builder()
+            .request(request)
+            .protocol(Protocol.HTTP_2)
+            .code(200)
+            .message("hello")
+            .build()
+
+        override fun connection(): Connection = error("Unsupported")
+
+        override fun call(): Call = error("Unsupported")
+
+        override fun connectTimeoutMillis(): Int = error("Unsupported")
+
+        override fun withConnectTimeout(timeout: Int, unit: TimeUnit): Interceptor.Chain = error("Unsupported")
+
+        override fun readTimeoutMillis(): Int = error("Unsupported")
+
+        override fun withReadTimeout(timeout: Int, unit: TimeUnit): Interceptor.Chain = error("Unsupported")
+
+        override fun writeTimeoutMillis(): Int = error("Unsupported")
+
+        override fun withWriteTimeout(timeout: Int, unit: TimeUnit): Interceptor.Chain = error("Unsupported")
+    }
+
+    @Test
+    fun `normal characters are supported`() {
+        assertEquals(
+            UserAgentHeaderInterceptor(userAgent = "test").intercept(createChain()).request().header("User-Agent"),
+            "test"
+        )
+    }
+
+    @Test
+    fun `special characters are supported`() {
+        assertEquals(
+            UserAgentHeaderInterceptor(userAgent = "test²").intercept(createChain()).request().header("User-Agent"),
+            "test²"
+        )
+    }
+}