diff --git a/changelog/fix_error_for_lint_unmodified_reduce_accumulator.md b/changelog/fix_error_for_lint_unmodified_reduce_accumulator.md
new file mode 100644
index 000000000000..f465bad696b3
--- /dev/null
+++ b/changelog/fix_error_for_lint_unmodified_reduce_accumulator.md
@@ -0,0 +1 @@
+* [#12997](https://github.com/rubocop/rubocop/pull/12997): Fix an error for `Lint/UnmodifiedReduceAccumulator` when the block is empty. ([@earlopain][])
diff --git a/lib/rubocop/cop/lint/unmodified_reduce_accumulator.rb b/lib/rubocop/cop/lint/unmodified_reduce_accumulator.rb
index 24fa303d4131..a8f9c36807e3 100644
--- a/lib/rubocop/cop/lint/unmodified_reduce_accumulator.rb
+++ b/lib/rubocop/cop/lint/unmodified_reduce_accumulator.rb
@@ -113,6 +113,7 @@ class UnmodifiedReduceAccumulator < Base
         PATTERN
 
         def on_block(node)
+          return unless node.body
           return unless reduce_with_block?(node)
           return unless node.argument_list.length >= 2
 
diff --git a/spec/rubocop/cop/lint/unmodified_reduce_accumulator_spec.rb b/spec/rubocop/cop/lint/unmodified_reduce_accumulator_spec.rb
index 220eb3956acc..0731b16d551a 100644
--- a/spec/rubocop/cop/lint/unmodified_reduce_accumulator_spec.rb
+++ b/spec/rubocop/cop/lint/unmodified_reduce_accumulator_spec.rb
@@ -16,6 +16,12 @@
       RUBY
     end
 
+    it "does not affect #{method} called with an empty block" do
+      expect_no_offenses(<<~RUBY)
+        values.#{method}(:+) { |result, value| }
+      RUBY
+    end
+
     context "given a #{method} block" do
       it 'does not register an offense when returning a literal' do
         expect_no_offenses(<<~RUBY)