diff --git a/packages/runtime-core/__tests__/helpers/useTemplateRef.spec.ts b/packages/runtime-core/__tests__/helpers/useTemplateRef.spec.ts
index adc8ed66c77..3dc0005bf6e 100644
--- a/packages/runtime-core/__tests__/helpers/useTemplateRef.spec.ts
+++ b/packages/runtime-core/__tests__/helpers/useTemplateRef.spec.ts
@@ -125,4 +125,28 @@ describe('useTemplateRef', () => {
       __DEV__ = true
     }
   })
+
+  // 12246
+  test('should set last element if multiple with same key are defined', () => {
+    let tRef: ShallowRef
+    let key = 'refKey'
+
+    const Comp = {
+      setup() {
+        tRef = useTemplateRef(key)
+      },
+      render() {
+        return h('div', [
+          h('div', { ref: key }),
+          h('div', { ref: key }),
+          h('span', { ref: key }),
+        ])
+      },
+    }
+
+    const root = nodeOps.createElement('div')
+    render(h(Comp), root)
+
+    expect(tRef!.value.tag).toBe('span')
+  })
 })
diff --git a/packages/runtime-core/__tests__/rendererTemplateRef.spec.ts b/packages/runtime-core/__tests__/rendererTemplateRef.spec.ts
index 64cb9c63014..68f24055c1c 100644
--- a/packages/runtime-core/__tests__/rendererTemplateRef.spec.ts
+++ b/packages/runtime-core/__tests__/rendererTemplateRef.spec.ts
@@ -1,4 +1,5 @@
 import {
+  type ShallowRef,
   defineComponent,
   h,
   nextTick,
@@ -538,4 +539,27 @@ describe('api: template refs', () => {
       '<div><div>[object Object],[object Object]</div><ul><li>2</li><li>3</li></ul></div>',
     )
   })
+
+  // 12246
+  test('should set last element if multiple with same key are defined', () => {
+    let refKey: ShallowRef
+
+    const Comp = {
+      setup() {
+        refKey = ref()
+      },
+      render() {
+        return h('div', [
+          h('div', { ref: refKey }),
+          h('div', { ref: refKey }),
+          h('span', { ref: refKey }),
+        ])
+      },
+    }
+
+    const root = nodeOps.createElement('div')
+    render(h(Comp), root)
+
+    expect(refKey!.value.tag).toBe('span')
+  })
 })
diff --git a/packages/runtime-core/src/rendererTemplateRef.ts b/packages/runtime-core/src/rendererTemplateRef.ts
index bffe1a25321..29e5d3c0c13 100644
--- a/packages/runtime-core/src/rendererTemplateRef.ts
+++ b/packages/runtime-core/src/rendererTemplateRef.ts
@@ -115,6 +115,16 @@ export function setRef(
           } else {
             if (!isArray(existing)) {
               if (_isString) {
+                if (oldRef === ref) {
+                  if (__DEV__ && !__TEST__) {
+                    warn(
+                      'Duplicate template ref detected:',
+                      ref,
+                      `(${typeof ref}). Ref names must be unique within the same scope.`,
+                    )
+                  }
+                  return
+                }
                 refs[ref] = [refValue]
                 if (canSetSetupRef(ref)) {
                   setupState[ref] = refs[ref]
@@ -128,6 +138,16 @@ export function setRef(
             }
           }
         } else if (_isString) {
+          if (oldRef === ref) {
+            if (__DEV__ && !__TEST__) {
+              warn(
+                'Duplicate template ref detected:',
+                ref,
+                `(${typeof ref}). Ref names must be unique within the same scope.`,
+              )
+            }
+            return
+          }
           refs[ref] = value
           if (canSetSetupRef(ref)) {
             setupState[ref] = value