diff --git a/core/utils/deprecation.ts b/core/utils/deprecation.ts
index da7977c3e84..c793b5f57dd 100644
--- a/core/utils/deprecation.ts
+++ b/core/utils/deprecation.ts
@@ -6,6 +6,9 @@
 
 // Former goog.module ID: Blockly.utils.deprecation
 
+// Set of previously-emitted warnings.
+const previousWarnings = new Set();
+
 /**
  * Warn developers that a function or property is deprecated.
  *
@@ -33,5 +36,12 @@ export function warn(
   if (opt_use) {
     msg += '\nUse ' + opt_use + ' instead.';
   }
+
+  // Don't log deprecation warnings multiple times.
+  if (previousWarnings.has(msg)) {
+    return;
+  }
+
+  previousWarnings.add(msg);
   console.warn(msg);
 }