diff --git a/lib/rules/sort-comp.js b/lib/rules/sort-comp.js
index e5e141fcb1..5c3e8f7ccb 100644
--- a/lib/rules/sort-comp.js
+++ b/lib/rules/sort-comp.js
@@ -384,10 +384,11 @@ module.exports = {
           node.value.type !== 'ArrowFunctionExpression' &&
           node.value.type !== 'FunctionExpression',
         instanceMethod: !node.static &&
-          node.type === 'ClassProperty' &&
           node.value &&
-          (node.value.type === 'ArrowFunctionExpression' ||
-            node.value.type === 'FunctionExpression'),
+          (
+            (node.type === 'ClassProperty' && node.value.type === 'ArrowFunctionExpression') ||
+            (node.type === 'MethodDefinition' && node.value.type === 'FunctionExpression')
+          ),
         typeAnnotation: !!node.typeAnnotation && node.value === null
       }));
 
diff --git a/tests/lib/rules/sort-comp.js b/tests/lib/rules/sort-comp.js
index ac9da200a3..5de2f037fd 100644
--- a/tests/lib/rules/sort-comp.js
+++ b/tests/lib/rules/sort-comp.js
@@ -315,8 +315,8 @@ ruleTester.run('sort-comp', rule, {
     code: [
       'class Hello extends React.Component {',
       '  foo = () => {}',
-      '  constructor() {}',
       '  classMethod() {}',
+      '  constructor() {}',
       '  static bar = () => {}',
       '  render() {',
       '    return <div>{this.props.text}</div>;',
@@ -573,7 +573,7 @@ ruleTester.run('sort-comp', rule, {
       '}'
     ].join('\n'),
     parser: 'babel-eslint',
-    errors: [{message: 'foo should be placed before constructor'}],
+    errors: [{message: 'classMethod should be placed before constructor'}],
     options: [{
       order: [
         'instance-methods',