diff --git a/packages/eslint-plugin/src/rules/triple-slash-reference.ts b/packages/eslint-plugin/src/rules/triple-slash-reference.ts
index 1bb16c229a1..08c3ad6291b 100644
--- a/packages/eslint-plugin/src/rules/triple-slash-reference.ts
+++ b/packages/eslint-plugin/src/rules/triple-slash-reference.ts
@@ -1,4 +1,5 @@
 import {
+  AST_NODE_TYPES,
   AST_TOKEN_TYPES,
   TSESTree,
 } from '@typescript-eslint/experimental-utils';
@@ -81,9 +82,11 @@ export default util.createRule<Options, MessageIds>({
       },
       TSImportEqualsDeclaration(node): void {
         if (programNode) {
-          const source = (node.moduleReference as TSESTree.TSExternalModuleReference)
-            .expression as TSESTree.Literal;
-          hasMatchingReference(source);
+          const reference = node.moduleReference;
+
+          if (reference.type === AST_NODE_TYPES.TSExternalModuleReference) {
+            hasMatchingReference(reference.expression as TSESTree.Literal);
+          }
         }
       },
       Program(node): void {
diff --git a/packages/eslint-plugin/tests/rules/triple-slash-reference.test.ts b/packages/eslint-plugin/tests/rules/triple-slash-reference.test.ts
index ab10ba5f6d9..8dd71212fbb 100644
--- a/packages/eslint-plugin/tests/rules/triple-slash-reference.test.ts
+++ b/packages/eslint-plugin/tests/rules/triple-slash-reference.test.ts
@@ -54,6 +54,28 @@ ruleTester.run('triple-slash-reference', rule, {
       `,
       options: [{ path: 'always', types: 'always', lib: 'always' }],
     },
+    {
+      code: `
+        /// <reference path="foo" />
+        /// <reference types="bar" />
+        /// <reference lib="baz" />
+        import foo = foo;
+        import bar = bar;
+        import baz = baz;
+      `,
+      options: [{ path: 'always', types: 'always', lib: 'always' }],
+    },
+    {
+      code: `
+        /// <reference path="foo" />
+        /// <reference types="bar" />
+        /// <reference lib="baz" />
+        import foo = foo.foo;
+        import bar = bar.bar.bar.bar;
+        import baz = baz.baz;
+      `,
+      options: [{ path: 'always', types: 'always', lib: 'always' }],
+    },
     {
       code: "import * as foo from 'foo';",
       options: [{ path: 'never' }],