diff --git a/packages/eslint-plugin/src/rules/max-params.ts b/packages/eslint-plugin/src/rules/max-params.ts
index acd02f052d15..c2920e901c16 100644
--- a/packages/eslint-plugin/src/rules/max-params.ts
+++ b/packages/eslint-plugin/src/rules/max-params.ts
@@ -13,7 +13,9 @@ import { getESLintCoreRule } from '../util/getESLintCoreRule';
 type FunctionLike =
   | TSESTree.ArrowFunctionExpression
   | TSESTree.FunctionDeclaration
-  | TSESTree.FunctionExpression;
+  | TSESTree.FunctionExpression
+  | TSESTree.TSDeclareFunction
+  | TSESTree.TSFunctionType;
 
 type FunctionRuleListener<T extends FunctionLike> = (node: T) => void;
 
@@ -97,6 +99,8 @@ export default createRule<Options, MessageIds>({
       ArrowFunctionExpression: wrapListener(baseRules.ArrowFunctionExpression),
       FunctionDeclaration: wrapListener(baseRules.FunctionDeclaration),
       FunctionExpression: wrapListener(baseRules.FunctionExpression),
+      TSDeclareFunction: wrapListener(baseRules.FunctionDeclaration),
+      TSFunctionType: wrapListener(baseRules.FunctionDeclaration),
     };
   },
 });
diff --git a/packages/eslint-plugin/tests/rules/max-params.test.ts b/packages/eslint-plugin/tests/rules/max-params.test.ts
index 0bbbdcdc92be..3edbd34ae346 100644
--- a/packages/eslint-plugin/tests/rules/max-params.test.ts
+++ b/packages/eslint-plugin/tests/rules/max-params.test.ts
@@ -57,6 +57,18 @@ class Foo {
       `,
       options: [{ countVoidThis: true, max: 2 }],
     },
+    {
+      code: `
+declare function makeDate(m: number, d: number, y: number): Date;
+      `,
+      options: [{ max: 3 }],
+    },
+    {
+      code: `
+type sum = (a: number, b: number) => number;
+      `,
+      options: [{ max: 2 }],
+    },
   ],
   invalid: [
     { code: 'function foo(a, b, c, d) {}', errors: [{ messageId: 'exceed' }] },
@@ -98,5 +110,19 @@ class Foo {
       `,
       errors: [{ messageId: 'exceed' }],
     },
+    {
+      code: `
+declare function makeDate(m: number, d: number, y: number): Date;
+      `,
+      errors: [{ messageId: 'exceed' }],
+      options: [{ max: 1 }],
+    },
+    {
+      code: `
+type sum = (a: number, b: number) => number;
+      `,
+      errors: [{ messageId: 'exceed' }],
+      options: [{ max: 1 }],
+    },
   ],
 });
diff --git a/packages/eslint-plugin/typings/eslint-rules.d.ts b/packages/eslint-plugin/typings/eslint-rules.d.ts
index a946d3365a55..6632125e3b15 100644
--- a/packages/eslint-plugin/typings/eslint-rules.d.ts
+++ b/packages/eslint-plugin/typings/eslint-rules.d.ts
@@ -113,7 +113,12 @@ declare module 'eslint/lib/rules/max-params' {
     unknown,
     {
       ArrowFunctionExpression(node: TSESTree.ArrowFunctionExpression): void;
-      FunctionDeclaration(node: TSESTree.FunctionDeclaration): void;
+      FunctionDeclaration(
+        node:
+          | TSESTree.FunctionDeclaration
+          | TSESTree.TSDeclareFunction
+          | TSESTree.TSFunctionType,
+      ): void;
       FunctionExpression(node: TSESTree.FunctionExpression): void;
     }
   >;