diff --git a/include/picrin/pair.h b/include/picrin/pair.h
index 82584b0c..2d5a02b2 100644
--- a/include/picrin/pair.h
+++ b/include/picrin/pair.h
@@ -5,6 +5,7 @@ pic_value pic_cons(pic_state *, pic_value, pic_value);
 pic_value pic_car(pic_state *, pic_value);
 pic_value pic_cdr(pic_state *, pic_value);
 
+bool pic_list_p(pic_state *, pic_value);
 pic_value pic_list(pic_state *, size_t, ...);
 
 pic_value pic_assq(pic_state *, pic_value key, pic_value assoc);
diff --git a/src/pair.c b/src/pair.c
index bbd17e5f..63fa1e40 100644
--- a/src/pair.c
+++ b/src/pair.c
@@ -39,6 +39,15 @@ pic_cdr(pic_state *pic, pic_value obj)
   return pair->cdr;
 }
 
+bool
+pic_list_p(pic_state *pic, pic_value obj)
+{
+  while (pic_pair_p(obj))
+    obj = pic_pair_ptr(obj)->cdr;
+
+  return pic_nil_p(obj);
+}
+
 pic_value
 pic_assq(pic_state *pic, pic_value key, pic_value assoc)
 {