diff --git a/changelog/fix_multiple_assertions_false_positive_methods_with_receiver.md b/changelog/fix_multiple_assertions_false_positive_methods_with_receiver.md
new file mode 100644
index 00000000..ea1f85f6
--- /dev/null
+++ b/changelog/fix_multiple_assertions_false_positive_methods_with_receiver.md
@@ -0,0 +1 @@
+* [#321](https://github.com/rubocop/rubocop-minitest/issues/321): Fix a false positive for `Minitest/MultipleAssertions` for assert_/refute_ methods with a receiver. ([@MatzFan][])
diff --git a/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb b/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
index ffa39ce2..4bb7382c 100644
--- a/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
+++ b/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
@@ -99,7 +99,7 @@ def assertions_count(node)
         end
       end
 
-      # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
+      # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Metrics/AbcSize
       def assertion_method?(node)
         return false unless node
         return assertion_method?(node.expression) if node.assignment? && node.respond_to?(:expression)
@@ -108,10 +108,10 @@ def assertion_method?(node)
         ASSERTION_PREFIXES.any? do |prefix|
           method_name = node.method_name
 
-          method_name.start_with?(prefix) || node.method?(:flunk)
+          (method_name.start_with?(prefix) && !node.receiver) || node.method?(:flunk)
         end
       end
-      # rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
+      # rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Metrics/AbcSize
 
       def lifecycle_hook_method?(node)
         node.def_type? && LIFECYCLE_HOOK_METHODS.include?(node.method_name)
diff --git a/test/rubocop/cop/minitest/multiple_assertions_test.rb b/test/rubocop/cop/minitest/multiple_assertions_test.rb
index 0509c12f..3a1ea2b4 100644
--- a/test/rubocop/cop/minitest/multiple_assertions_test.rb
+++ b/test/rubocop/cop/minitest/multiple_assertions_test.rb
@@ -7,6 +7,17 @@ def setup
     configure_max_assertions(1)
   end
 
+  def test_checks_only_assertion_methods_with_no_receiver
+    assert_no_offenses(<<~RUBY)
+      class FooTest < Minitest::Test
+        # assert_something has a receiver 
+        def test_asserts_once
+          assert_equal(foo, Bar.assert_something)
+        end
+      end
+    RUBY
+  end
+
   def test_registers_offense_when_multiple_expectations
     assert_offense(<<~RUBY)
       class FooTest < Minitest::Test