diff --git a/.changeset/ten-lamps-sell.md b/.changeset/ten-lamps-sell.md
new file mode 100644
index 000000000..31236d0e0
--- /dev/null
+++ b/.changeset/ten-lamps-sell.md
@@ -0,0 +1,5 @@
+---
+"eslint-plugin-import-x": patch
+---
+
+Fix #144, read proper `sourceType` for both eslint flat config and legacy eslintrc config.
diff --git a/src/rules/no-default-export.ts b/src/rules/no-default-export.ts
index 8cb95b8ca..2456b316b 100644
--- a/src/rules/no-default-export.ts
+++ b/src/rules/no-default-export.ts
@@ -1,4 +1,5 @@
 import { createRule } from '../utils'
+import sourceType from '../utils/source-type'
 
 export = createRule({
   name: 'no-default-export',
@@ -18,7 +19,7 @@ export = createRule({
   defaultOptions: [],
   create(context) {
     // ignore non-modules
-    if (context.parserOptions.sourceType !== 'module') {
+    if (sourceType(context) !== 'module') {
       return {}
     }
 
diff --git a/src/rules/no-named-export.ts b/src/rules/no-named-export.ts
index 3cc2434f1..1282a6fe3 100644
--- a/src/rules/no-named-export.ts
+++ b/src/rules/no-named-export.ts
@@ -1,4 +1,5 @@
 import { createRule } from '../utils'
+import sourceType from '../utils/source-type'
 
 export = createRule({
   name: 'no-named-export',
@@ -16,7 +17,7 @@ export = createRule({
   defaultOptions: [],
   create(context) {
     // ignore non-modules
-    if (context.parserOptions.sourceType !== 'module') {
+    if (sourceType(context) !== 'module') {
       return {}
     }
 
diff --git a/src/rules/unambiguous.ts b/src/rules/unambiguous.ts
index 119c125dd..b878bac85 100644
--- a/src/rules/unambiguous.ts
+++ b/src/rules/unambiguous.ts
@@ -3,6 +3,7 @@
  */
 
 import { createRule, isUnambiguousModule } from '../utils'
+import sourceType from '../utils/source-type'
 
 export = createRule({
   name: 'unambiguous',
@@ -21,7 +22,7 @@ export = createRule({
   defaultOptions: [],
   create(context) {
     // ignore non-modules
-    if (context.parserOptions.sourceType !== 'module') {
+    if (sourceType(context) !== 'module') {
       return {}
     }
 
diff --git a/src/utils/source-type.ts b/src/utils/source-type.ts
new file mode 100644
index 000000000..89f732e4b
--- /dev/null
+++ b/src/utils/source-type.ts
@@ -0,0 +1,10 @@
+import type { RuleContext } from '../types'
+
+export default function sourceType(context: RuleContext) {
+  if ('sourceType' in context.parserOptions) {
+    return context.parserOptions.sourceType
+  }
+  if ('languageOptions' in context && context.languageOptions) {
+    return context.languageOptions.sourceType
+  }
+}
diff --git a/test/rules/no-default-export.spec.ts b/test/rules/no-default-export.spec.ts
index e38ce7b6e..92ef91f0e 100644
--- a/test/rules/no-default-export.spec.ts
+++ b/test/rules/no-default-export.spec.ts
@@ -165,6 +165,25 @@ ruleTester.run('no-default-export', rule, {
         },
       ],
     }),
+    test({
+      code: "function foo() { return 'foo'; }\nexport default foo;",
+      filename: 'foo.ts',
+      errors: [
+        {
+          type: 'ExportDefaultDeclaration',
+          messageId: 'preferNamed',
+        },
+      ],
+      languageOptions: {
+        parserOptions: {
+          ecmaversion: 'latest',
+          sourceType: 'module',
+        },
+      },
+      settings: {
+        'import-x/resolver': { typescript: true },
+      },
+    }),
     test({
       code: 'export default from "foo.js"',
       languageOptions: { parser: require(parsers.BABEL) },