diff --git a/jspecify_migration.py b/jspecify_migration.py
new file mode 100644
index 000000000000..ac9c4016488f
--- /dev/null
+++ b/jspecify_migration.py
@@ -0,0 +1,78 @@
+import os
+import re
+
+def migrate_file(file_path):
+    with open(file_path, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    original_content = content
+    
+    # 1. Add JSpecify NullMarked import if not present
+    package_match = re.search(r"^(package\s+[\w\.]+;)", content, re.MULTILINE)
+    if package_match and "org.jspecify.annotations.NullMarked" not in content and "@NullMarked" not in content:
+        package_line = package_match.group(1)
+        content = content.replace(package_line, package_line + "\nimport org.jspecify.annotations.NullMarked;")
+        
+        # 2. Add @NullMarked before class/interface/enum declaration
+        class_match = re.search(r"\n(public\s+)?(abstract\s+)?(final\s+)?(class|interface|enum)\s+\w+", content)
+        if class_match:
+            class_start = class_match.start()
+            prefix = content[:class_start]
+            lines = prefix.split("\n")
+            
+            # Find the correct insertion point (before other class-level annotations)
+            insert_idx = len(lines)
+            for i in range(len(lines) - 1, -1, -1):
+                line = lines[i].strip()
+                if line.startswith("@") and not line.startswith("@Override") and not line.startswith("@Test"):
+                    insert_idx = i
+                elif line == "" or line.startswith("//") or line.startswith("/*") or line.startswith("*"):
+                    break
+                else:
+                    break
+            lines.insert(insert_idx, "@NullMarked")
+            content = "\n".join(lines) + content[class_start:]
+
+
+    # 3. Replace legacy javax Nullable import
+    content = content.replace("import javax.annotation.Nullable;", "import org.jspecify.annotations.Nullable;")
+
+    # 4. Reposition @Nullable from declaration to type-use position
+    # (immediately before the type name, after class modifiers)
+    patterns = [
+        (r"@Nullable\s+public\s+abstract\s+final\s+(\w+)", r"public abstract final @Nullable \1"),
+        (r"@Nullable\s+public\s+abstract\s+(\w+)", r"public abstract @Nullable \1"),
+        (r"@Nullable\s+public\s+static\s+final\s+(\w+)", r"public static final @Nullable \1"),
+        (r"@Nullable\s+public\s+static\s+(\w+)", r"public static @Nullable \1"),
+        (r"@Nullable\s+public\s+final\s+(\w+)", r"public final @Nullable \1"),
+        (r"@Nullable\s+public\s+(\w+)", r"public @Nullable \1"),
+        (r"@Nullable\s+private\s+static\s+final\s+(\w+)", r"private static final @Nullable \1"),
+        (r"@Nullable\s+private\s+static\s+(\w+)", r"private static @Nullable \1"),
+        (r"@Nullable\s+private\s+final\s+(\w+)", r"private final @Nullable \1"),
+        (r"@Nullable\s+private\s+(\w+)", r"private @Nullable \1"),
+        (r"@Nullable\s+protected\s+static\s+final\s+(\w+)", r"protected static final @Nullable \1"),
+        (r"@Nullable\s+protected\s+static\s+(\w+)", r"protected static @Nullable \1"),
+        (r"@Nullable\s+protected\s+final\s+(\w+)", r"protected final @Nullable \1"),
+        (r"@Nullable\s+protected\s+(\w+)", r"protected @Nullable \1"),
+    ]
+
+    for pattern, replacement in patterns:
+        content = re.sub(pattern, replacement, content)
+
+    # Save changes if modified
+    if content != original_content:
+        with open(file_path, "w", encoding="utf-8") as f:
+            f.write(content)
+
+def walk_and_migrate(directory):
+    for root, _, files in os.walk(directory):
+        for file in files:
+            if file.endswith(".java") and file != "package-info.java":
+                migrate_file(os.path.join(root, file))
+
+if __name__ == "__main__":
+    import sys
+    if len(sys.argv) > 1:
+        walk_and_migrate(sys.argv[1])
+    else:
+        print("Usage: python jspecify_migration.py <directory_path>")