diff --git a/lib/livebook/runtime/evaluator/doctests.ex b/lib/livebook/runtime/evaluator/doctests.ex
index 81e64528f..fc6e543e6 100644
--- a/lib/livebook/runtime/evaluator/doctests.ex
+++ b/lib/livebook/runtime/evaluator/doctests.ex
@@ -163,7 +163,13 @@ defmodule Livebook.Runtime.Evaluator.Doctests do
 
     expected = diff[:right]
     got = diff[:left]
-    source = String.trim(reason.doctest)
+
+    {expected_label, got_label, source} =
+      if reason.doctest == ExUnit.AssertionError.no_value() do
+        {"right", "left", nil}
+      else
+        {"expected", "got", String.trim(reason.doctest)}
+      end
 
     message_io =
       if_io(reason.message != "Doctest failed", fn ->
@@ -175,19 +181,22 @@ defmodule Livebook.Runtime.Evaluator.Doctests do
         [colorize(:red, message), "\n"]
       end)
 
-    source_io = [
-      String.duplicate(" ", @pad_size),
-      format_label("doctest"),
-      "\n",
-      pad(source, @pad_size + 2)
-    ]
+    source_io =
+      if_io(source, fn ->
+        [
+          String.duplicate(" ", @pad_size),
+          format_label("doctest"),
+          "\n",
+          pad(source, @pad_size + 2)
+        ]
+      end)
 
     expected_io =
       if_io(expected, fn ->
         [
           "\n",
           String.duplicate(" ", @pad_size),
-          format_label("expected"),
+          format_label(expected_label),
           "\n",
           String.duplicate(" ", @pad_size + 2),
           expected
@@ -199,7 +208,7 @@ defmodule Livebook.Runtime.Evaluator.Doctests do
         [
           "\n",
           String.duplicate(" ", @pad_size),
-          format_label("got"),
+          format_label(got_label),
           "\n",
           String.duplicate(" ", @pad_size + 2),
           got
diff --git a/test/livebook/runtime/evaluator_test.exs b/test/livebook/runtime/evaluator_test.exs
index 739a59d4c..a70169c44 100644
--- a/test/livebook/runtime/evaluator_test.exs
+++ b/test/livebook/runtime/evaluator_test.exs
@@ -401,6 +401,11 @@ defmodule Livebook.Runtime.EvaluatorTest do
 
             iex> 1 +
             :who_knows
+
+            iex> 1 = 2
+
+            iex> require ExUnit.Assertions
+            ...> ExUnit.Assertions.assert false
         """
 
         @doc """
@@ -444,7 +449,7 @@ defmodule Livebook.Runtime.EvaluatorTest do
 
       assert_receive {:runtime_evaluation_output, :code_1, {:text, doctest_result}}
 
-      assert doctest_result =~ "6 doctests, 5 failures"
+      assert doctest_result =~ "8 doctests, 7 failures"
       assert doctest_result =~ "Doctest did not compile, got: (TokenMissingError)"
 
       assert doctest_result =~