diff --git a/common/changes/@microsoft/rush/eric.prestemon-fix-5552_2026-02-18-01-11.json b/common/changes/@microsoft/rush/eric.prestemon-fix-5552_2026-02-18-01-11.json
new file mode 100644
index 00000000000..213e3ec34ef
--- /dev/null
+++ b/common/changes/@microsoft/rush/eric.prestemon-fix-5552_2026-02-18-01-11.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Sort the `additionalFilesForOperation` property in operation settings entries in projects' `config/rush-project.json` files before computing operation hashes to produce a stable hash for caching.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@microsoft/rush"
+}
\ No newline at end of file
diff --git a/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts b/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts
index 8eeaa5ed224..0568558d014 100644
--- a/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts
+++ b/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts
@@ -318,7 +318,9 @@ export class InputsSnapshot implements IInputsSnapshot {
         const additionalFilesForOperation: ReadonlySet<string> | undefined =
           record.additionalFilesByOperationName?.get(operationName);
         if (additionalFilesForOperation) {
-          for (const [filePath, hash] of this._resolveHashes(additionalFilesForOperation)) {
+          // Sort the additional files to ensure deterministic hash computation
+          const sortedAdditionalFiles: string[] = Array.from(additionalFilesForOperation).sort();
+          for (const [filePath, hash] of this._resolveHashes(sortedAdditionalFiles)) {
             hashes.set(filePath, hash);
           }
         }