diff --git a/packages/eslint-plugin/tests/rules/only-throw-error.test.ts b/packages/eslint-plugin/tests/rules/only-throw-error.test.ts
index 6f60f01b8405..500454d0a9cb 100644
--- a/packages/eslint-plugin/tests/rules/only-throw-error.test.ts
+++ b/packages/eslint-plugin/tests/rules/only-throw-error.test.ts
@@ -191,6 +191,19 @@ throw new Map();
     },
     {
       code: `
+function func<T1, T2>() {
+  let err: Promise<T1> | Promise<T2>;
+  throw err;
+}
+      `,
+      options: [
+        {
+          allow: ['Promise'],
+        },
+      ],
+    },
+    {
+      code: `
 try {
 } catch (e) {
   throw e;
@@ -615,6 +628,24 @@ function fun<T extends number>(t: T): void {
     },
     {
       code: `
+function func<T1, T2>() {
+  let err: Promise<T1> | Promise<T2> | void;
+  throw err;
+}
+      `,
+      errors: [
+        {
+          messageId: 'object',
+        },
+      ],
+      options: [
+        {
+          allow: ['Promise'],
+        },
+      ],
+    },
+    {
+      code: `
 class UnknownError implements Error {}
 throw new UnknownError();
       `,
diff --git a/packages/type-utils/src/TypeOrValueSpecifier.ts b/packages/type-utils/src/TypeOrValueSpecifier.ts
index bbfb99ddcc78..553c8a4225bf 100644
--- a/packages/type-utils/src/TypeOrValueSpecifier.ts
+++ b/packages/type-utils/src/TypeOrValueSpecifier.ts
@@ -169,6 +169,10 @@ export function typeMatchesSpecifier(
   specifier: TypeOrValueSpecifier,
   program: ts.Program,
 ): boolean {
+  if (tsutils.isUnionType(type)) {
+    return type.types.every(t => typeMatchesSpecifier(t, specifier, program));
+  }
+
   const wholeTypeMatches = ((): boolean => {
     if (tsutils.isIntrinsicErrorType(type)) {
       return false;
diff --git a/packages/type-utils/tests/TypeOrValueSpecifier.test.ts b/packages/type-utils/tests/TypeOrValueSpecifier.test.ts
index a28d22f36b71..3d3429fbb3d1 100644
--- a/packages/type-utils/tests/TypeOrValueSpecifier.test.ts
+++ b/packages/type-utils/tests/TypeOrValueSpecifier.test.ts
@@ -179,6 +179,7 @@ describe('TypeOrValueSpecifier', () => {
       ['interface Foo {prop: string}; type Test = Foo;', 'RegExp'],
       ['type Test = RegExp;', 'Foo'],
       ['type Test = RegExp;', 'BigInt'],
+      ['type Test = RegExp | BigInt;', 'BigInt'],
     ] as const satisfies [string, TypeOrValueSpecifier][])(
       "doesn't match a mismatched universal string specifier: %s\n\t%s",
       ([code, typeOrValueSpecifier], { expect }) => {
@@ -267,6 +268,10 @@ describe('TypeOrValueSpecifier', () => {
         'interface Foo {prop: string}; type Test = Foo;',
         { from: 'file', name: 'Bar' },
       ],
+      [
+        'interface Foo {prop: string}; type Test = Foo | string;',
+        { from: 'file', name: 'Foo' },
+      ],
       [
         'interface Foo {prop: string}; type Test = Foo;',
         { from: 'file', name: ['Bar', 'Baz'] },
@@ -306,6 +311,7 @@ describe('TypeOrValueSpecifier', () => {
 
     it.for([
       ['type Test = RegExp;', { from: 'lib', name: 'BigInt' }],
+      ['type Test = RegExp | BigInt;', { from: 'lib', name: 'BigInt' }],
       ['type Test = RegExp;', { from: 'lib', name: ['BigInt', 'Date'] }],
     ] as const satisfies [string, TypeOrValueSpecifier][])(
       "doesn't match a mismatched lib specifier: %s\n\t%s",
@@ -326,6 +332,7 @@ describe('TypeOrValueSpecifier', () => {
 
     it.for([
       ['type Test = string;', { from: 'lib', name: 'number' }],
+      ['type Test = string | number;', { from: 'lib', name: 'number' }],
       ['type Test = string;', { from: 'lib', name: ['number', 'boolean'] }],
     ] as const satisfies [string, TypeOrValueSpecifier][])(
       "doesn't match a mismatched intrinsic type specifier: %s\n\t%s",
@@ -545,6 +552,10 @@ describe('TypeOrValueSpecifier', () => {
         'import type {Node} from "typescript"; type Test = Node;',
         { from: 'package', name: 'Symbol', package: 'typescript' },
       ],
+      [
+        'import type {Node} from "typescript"; type Test = Node | Symbol;',
+        { from: 'package', name: 'Node', package: 'typescript' },
+      ],
       [
         'import type {Node} from "typescript"; type Test = Node;',
         { from: 'package', name: ['Symbol', 'Checker'], package: 'typescript' },