diff --git a/prism/util/pm_string.c b/prism/util/pm_string.c
index 0a67accd86..4bd3dd8ef2 100644
--- a/prism/util/pm_string.c
+++ b/prism/util/pm_string.c
@@ -62,7 +62,7 @@ PRISM_EXPORTED_FUNCTION bool
 pm_string_mapped_init(pm_string_t *string, const char *filepath) {
 #ifdef _WIN32
     // Open the file for reading.
-    HANDLE file = CreateFile(filepath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    HANDLE file = CreateFile(filepath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL);
 
     if (file == INVALID_HANDLE_VALUE) {
         return false;
@@ -156,7 +156,7 @@ PRISM_EXPORTED_FUNCTION bool
 pm_string_file_init(pm_string_t *string, const char *filepath) {
 #ifdef _WIN32
     // Open the file for reading.
-    HANDLE file = CreateFile(filepath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    HANDLE file = CreateFile(filepath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL);
 
     if (file == INVALID_HANDLE_VALUE) {
         return false;
diff --git a/test/prism/api/parse_test.rb b/test/prism/api/parse_test.rb
index dda0d6959c..2e9722f5da 100644
--- a/test/prism/api/parse_test.rb
+++ b/test/prism/api/parse_test.rb
@@ -61,6 +61,14 @@ module Prism
       end
     end
 
+    def test_parse_tempfile
+      Tempfile.create(["test_parse_tempfile", ".rb"]) do |t|
+        t.puts ["begin\n", " end\n"]
+        t.flush
+        Prism.parse_file(t.path)
+      end
+    end
+
     private
 
     def find_source_file_node(program)