diff --git a/libs/langchain/langchain/output_parsers/json.py b/libs/langchain/langchain/output_parsers/json.py
index f0f653eca2..7465aba2fe 100644
--- a/libs/langchain/langchain/output_parsers/json.py
+++ b/libs/langchain/langchain/output_parsers/json.py
@@ -13,7 +13,7 @@ def _replace_new_line(match: re.Match[str]) -> str:
     value = re.sub(r"\n", r"\\n", value)
     value = re.sub(r"\r", r"\\r", value)
     value = re.sub(r"\t", r"\\t", value)
-    value = re.sub('"', r"\"", value)
+    value = re.sub(r'(?<!\\)"', r"\"", value)
 
     return match.group(1) + value + match.group(3)
 
diff --git a/libs/langchain/tests/unit_tests/output_parsers/test_json.py b/libs/langchain/tests/unit_tests/output_parsers/test_json.py
index afaa4bf64f..21bc600fd0 100644
--- a/libs/langchain/tests/unit_tests/output_parsers/test_json.py
+++ b/libs/langchain/tests/unit_tests/output_parsers/test_json.py
@@ -67,6 +67,34 @@ JSON_WITH_MARKDOWN_CODE_BLOCK_AND_NEWLINES = """```json
 }
 ```"""
 
+JSON_WITH_UNESCAPED_QUOTES_IN_NESTED_JSON = """```json
+{
+    "action": "Final Answer",
+    "action_input": "{"foo": "bar", "bar": "foo"}"
+}
+```"""
+
+JSON_WITH_ESCAPED_QUOTES_IN_NESTED_JSON = """```json
+{
+    "action": "Final Answer",
+    "action_input": "{\"foo\": \"bar\", \"bar\": \"foo\"}"
+}
+```"""
+
+JSON_WITH_PYTHON_DICT = """```json
+{
+    "action": "Final Answer",
+    "action_input": {"foo": "bar", "bar": "foo"}
+}
+```"""
+
+JSON_WITH_ESCAPED_DOUBLE_QUOTES_IN_NESTED_JSON = """```json
+{
+    "action": "Final Answer",
+    "action_input": "{\\"foo\\": \\"bar\\", \\"bar\\": \\"foo\\"}"
+}
+```"""
+
 NO_TICKS = """{
     "foo": "bar"
 }"""
@@ -131,3 +159,27 @@ def test_parse_json_with_code_blocks() -> None:
         "action": "Final Answer",
         "action_input": '```bar\n<div id="1" class="value">\n\ttext\n</div>```',
     }
+
+
+TEST_CASES_ESCAPED_QUOTES = [
+    JSON_WITH_UNESCAPED_QUOTES_IN_NESTED_JSON,
+    JSON_WITH_ESCAPED_QUOTES_IN_NESTED_JSON,
+    JSON_WITH_ESCAPED_DOUBLE_QUOTES_IN_NESTED_JSON,
+]
+
+
+@pytest.mark.parametrize("json_string", TEST_CASES_ESCAPED_QUOTES)
+def test_parse_nested_json_with_escaped_quotes(json_string: str) -> None:
+    parsed = parse_json_markdown(json_string)
+    assert parsed == {
+        "action": "Final Answer",
+        "action_input": '{"foo": "bar", "bar": "foo"}',
+    }
+
+
+def test_parse_json_with_python_dict() -> None:
+    parsed = parse_json_markdown(JSON_WITH_PYTHON_DICT)
+    assert parsed == {
+        "action": "Final Answer",
+        "action_input": {"foo": "bar", "bar": "foo"},
+    }