diff --git a/packages/eslint-plugin/src/rules/typedef.ts b/packages/eslint-plugin/src/rules/typedef.ts
index 3d9d76f3872..19c4244d9f9 100644
--- a/packages/eslint-plugin/src/rules/typedef.ts
+++ b/packages/eslint-plugin/src/rules/typedef.ts
@@ -79,6 +79,15 @@ export default util.createRule<[Options], MessageIds>({
             break;
           case AST_NODE_TYPES.TSParameterProperty:
             annotationNode = param.parameter;
+
+            // Check TS parameter property with default value like `constructor(private param: string = 'something') {}`
+            if (
+              annotationNode &&
+              annotationNode.type === AST_NODE_TYPES.AssignmentPattern
+            ) {
+              annotationNode = annotationNode.left;
+            }
+
             break;
           default:
             annotationNode = param;
diff --git a/packages/eslint-plugin/tests/rules/typedef.test.ts b/packages/eslint-plugin/tests/rules/typedef.test.ts
index d5ea514f59e..c9e35c356eb 100644
--- a/packages/eslint-plugin/tests/rules/typedef.test.ts
+++ b/packages/eslint-plugin/tests/rules/typedef.test.ts
@@ -109,6 +109,19 @@ ruleTester.run('typedef', rule, {
     `function receivesString({ a }: { a: string }): void { }`,
     `function receivesStrings({ a, b }: { [i: string ]: string }): void { }`,
     `function receivesNumber(a: number = 123): void { }`,
+    // Constructor parameters
+    `class Test {
+      constructor() {}
+    }`,
+    `class Test {
+      constructor(param: string) {}
+    }`,
+    `class Test {
+      constructor(param: string = 'something') {}
+    }`,
+    `class Test {
+      constructor(private param: string = 'something') {}
+    }`,
     // Method parameters
     `class Test {
       public method(x: number): number { return x; }
@@ -401,6 +414,40 @@ ruleTester.run('typedef', rule, {
         },
       ],
     },
+    // Constructor parameters
+    {
+      code: `class Test {
+        constructor(param) {}
+      }`,
+      errors: [
+        {
+          column: 21,
+          messageId: 'expectedTypedefNamed',
+        },
+      ],
+    },
+    {
+      code: `class Test {
+        constructor(param = 'something') {}
+      }`,
+      errors: [
+        {
+          column: 21,
+          messageId: 'expectedTypedef',
+        },
+      ],
+    },
+    {
+      code: `class Test {
+        constructor(private param = 'something') {}
+      }`,
+      errors: [
+        {
+          column: 21,
+          messageId: 'expectedTypedef',
+        },
+      ],
+    },
     // Method parameters
     {
       code: `class Test {