diff --git a/.changeset/tasty-kangaroos-bake.md b/.changeset/tasty-kangaroos-bake.md
new file mode 100644
index 000000000000..e27d0b8ca29a
--- /dev/null
+++ b/.changeset/tasty-kangaroos-bake.md
@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+Fix params serialization when send the trigger workflow API
+
+Previously, wrangler did not parse the params sending it as a string to workflow's services.
diff --git a/packages/wrangler/src/workflows/commands/trigger.ts b/packages/wrangler/src/workflows/commands/trigger.ts
index 6b5ae47f5b8e..a288cd0e8f3f 100644
--- a/packages/wrangler/src/workflows/commands/trigger.ts
+++ b/packages/wrangler/src/workflows/commands/trigger.ts
@@ -54,7 +54,7 @@ defineCommand({
 				headers: { "Content-Type": "application/json" },
 				body: JSON.stringify({
 					instance_id: args.id,
-					params: args.params.length != 0 ? args.params : undefined,
+					params: args.params.length != 0 ? JSON.parse(args.params) : undefined,
 				}),
 			}
 		);