diff --git a/lib/ts_utils/utils.py b/lib/ts_utils/utils.py
index bf87def015bf..d7dd6ac0fcba 100644
--- a/lib/ts_utils/utils.py
+++ b/lib/ts_utils/utils.py
@@ -28,6 +28,24 @@ def colored(text: str, color: str | None = None, **kwargs: Any) -> str:  # type:
         return text
 
 
+_REMOVE_COMMENT_RE = re.compile(
+    r"""
+    (\"(?:\\.|[^\\\"])*?\")  # matches literal strings
+    |
+    (\/\*.*?\*\/ | \/\/[^\r\n]*?(?:[\r\n]))  # matches single- and multi-line comments
+    """,
+    re.DOTALL | re.VERBOSE,
+)
+_REMOVE_TRAILING_COMMA_RE = re.compile(
+    r"""
+    (\"(?:\\.|[^\\\"])*?\")  # matches literal strings
+    |
+    ,\s*([\]}])  # matches commas before '}' or ']'
+    """,
+    re.DOTALL | re.VERBOSE,
+)
+
+
 PYTHON_VERSION: Final = f"{sys.version_info.major}.{sys.version_info.minor}"
 
 
@@ -35,13 +53,15 @@ def strip_comments(text: str) -> str:
     return text.split("#")[0].strip()
 
 
-def json5_to_json(text: str) -> str:
-    """Incomplete conversion from JSON5-like input to valid JSON."""
-    # Remove full-line // comments only
-    # (Can not remove inline comments)
-    text = re.sub(r"(?m)^\s*//.*\n?", "", text)
+def jsonc_to_json(text: str) -> str:
+    """Conversion from JSONC format input to valid JSON."""
+    # Remove comments
+    if not text.endswith("\n"):
+        text += "\n"
+    text = _REMOVE_COMMENT_RE.sub(lambda m: m.group(1) or "", text)
+
     # Remove trailing commas before } or ]
-    text = re.sub(r",\s*([}\]])", r"\1", text)
+    text = _REMOVE_TRAILING_COMMA_RE.sub(lambda m: m.group(1) or m.group(2), text)
     return text
 
 
diff --git a/tests/check_typeshed_structure.py b/tests/check_typeshed_structure.py
index dd986b3f3e8b..8c3892ff04a6 100755
--- a/tests/check_typeshed_structure.py
+++ b/tests/check_typeshed_structure.py
@@ -17,7 +17,7 @@
 from ts_utils.utils import (
     get_all_testcase_directories,
     get_gitignore_spec,
-    json5_to_json,
+    jsonc_to_json,
     parse_requirements,
     parse_stdlib_versions_file,
     spec_matches_path,
@@ -178,7 +178,7 @@ def check_requirement_pins() -> None:
 def check_pyright_exclude_order() -> None:
     """Check that 'exclude' entries in pyrightconfig.stricter.json are sorted alphabetically."""
     text = PYRIGHT_CONFIG.read_text(encoding="utf-8")
-    text = json5_to_json(text)
+    text = jsonc_to_json(text)
     data = json.loads(text)
     exclude: list[str] = data.get("exclude", [])