diff --git a/src/validations/constraints/STYLE.md b/src/validations/constraints/STYLE.md
index 6f3231179..4e5c05cc0 100644
--- a/src/validations/constraints/STYLE.md
+++ b/src/validations/constraints/STYLE.md
@@ -195,3 +195,66 @@ Below is a non-conformant example.
```
+
+### FCSR-3
+
+ID: `fcsr-3`
+
+Formal Name: FedRAMP Requires Constraints in the Context Alphabetically by ID
+
+State: Required
+
+Guidance: Developers MUST sort OSCAL constraint definitions in a file for each context by each of their `@id`s alphabetically, from upper case and then lower case respectively.
+
+#### FCSR-3 Conformant Example
+
+Below is a conformant example:
+
+```xml
+
+
+
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+
+
+```
+
+#### FCSR-3 Non-conformant Example
+
+Below is a non-conformant example.
+
+```xml
+
+
+
+
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+ Example of sorting.
+
+
+
+
+```