diff --git a/src/runtime/template_set.ts b/src/runtime/template_set.ts
index 4bcbe43e..e7d40403 100644
--- a/src/runtime/template_set.ts
+++ b/src/runtime/template_set.ts
@@ -66,6 +66,10 @@ export class TemplateSet {
 
   addTemplate(name: string, template: string | Element) {
     if (name in this.rawTemplates) {
+      // this check can be expensive, just silently ignore double definitions outside dev mode
+      if (!this.dev) {
+        return;
+      }
       const rawTemplate = this.rawTemplates[name];
       const currentAsString =
         typeof rawTemplate === "string"
diff --git a/tests/compiler/validation.test.ts b/tests/compiler/validation.test.ts
index e90eaf9e..01ded356 100644
--- a/tests/compiler/validation.test.ts
+++ b/tests/compiler/validation.test.ts
@@ -11,8 +11,8 @@ describe("basic validation", () => {
     expect(() => context.getTemplate("invalidname")).toThrow("Missing template");
   });
 
-  test("cannot add a different template with the same name", () => {
-    const context = new TemplateSet();
+  test("cannot add a different template with the same name in dev mode", () => {
+    const context = new TemplateSet({ dev: true });
     context.addTemplate("test", `<t/>`);
     // Same template with the same name is fine
     expect(() => context.addTemplate("test", "<t/>")).not.toThrow();
@@ -20,6 +20,13 @@ describe("basic validation", () => {
     expect(() => context.addTemplate("test", "<div/>")).toThrow("already defined");
   });
 
+  test("adding different template with same name outside dev mode silently ignores it", () => {
+    const context = new TemplateSet({ dev: false });
+    context.addTemplate("test", `<t/>`);
+    expect(() => context.addTemplate("test", "<div/>")).not.toThrow();
+    expect(context.rawTemplates.test).toBe("<t/>");
+  });
+
   test("invalid xml", () => {
     const template = "<div>";
     expect(() => snapshotTemplate(template)).toThrow("Invalid XML in template");