diff --git a/changelog/fix_error_for_style_multiline_ternary_operator.md b/changelog/fix_error_for_style_multiline_ternary_operator.md
new file mode 100644
index 000000000000..d95c296446c1
--- /dev/null
+++ b/changelog/fix_error_for_style_multiline_ternary_operator.md
@@ -0,0 +1 @@
+* [#12691](https://github.com/rubocop/rubocop/issues/12691): Fix an error for `Style/MultilineTernaryOperator` when nesting multiline ternary operators. ([@koic][])
diff --git a/lib/rubocop/cop/style/multiline_ternary_operator.rb b/lib/rubocop/cop/style/multiline_ternary_operator.rb
index 23a656eed724..03ec44f3eede 100644
--- a/lib/rubocop/cop/style/multiline_ternary_operator.rb
+++ b/lib/rubocop/cop/style/multiline_ternary_operator.rb
@@ -47,7 +47,11 @@ def on_if(node)
           message = enforce_single_line_ternary_operator?(node) ? MSG_SINGLE_LINE : MSG_IF
 
           add_offense(node, message: message) do |corrector|
+            next if part_of_ignored_node?(node)
+
             autocorrect(corrector, node)
+
+            ignore_node(node)
           end
         end
 
diff --git a/spec/rubocop/cop/style/multiline_ternary_operator_spec.rb b/spec/rubocop/cop/style/multiline_ternary_operator_spec.rb
index 51848de34cf2..0f23c97d3486 100644
--- a/spec/rubocop/cop/style/multiline_ternary_operator_spec.rb
+++ b/spec/rubocop/cop/style/multiline_ternary_operator_spec.rb
@@ -50,6 +50,28 @@
     RUBY
   end
 
+  it 'registers an offense and corrects when nesting multiline ternary operators' do
+    expect_offense(<<~RUBY)
+      cond_a? ? foo :
+      ^^^^^^^^^^^^^^^ Avoid multi-line ternary operators, use `if` or `unless` instead.
+        cond_b? ? bar :
+        ^^^^^^^^^^^^^^^ Avoid multi-line ternary operators, use `if` or `unless` instead.
+          cond_c? ? baz : qux
+    RUBY
+
+    expect_correction(<<~RUBY)
+      if cond_a?
+        foo
+      else
+        if cond_b?
+        bar
+      else
+        cond_c? ? baz : qux
+      end
+      end
+    RUBY
+  end
+
   it 'registers an offense and corrects when everything is on a separate line' do
     expect_offense(<<~RUBY)
       a = cond ?