diff --git a/docs/queries.md b/docs/queries.md
index 2f7afe8..e73a404 100644
--- a/docs/queries.md
+++ b/docs/queries.md
@@ -320,6 +320,10 @@ Each configuration entry generates one final repository class in the configured
 `<sql[].name>Repository`. Every named query of that entry becomes one method of
 that repository; sqlcj never generates a class per query.
 
+- Every generated repository file begins with the fixed notice
+  `// Code generated by sqlcj. DO NOT EDIT.`, followed by one blank line and the
+  `package` declaration. The notice holds no version, timestamp, or filesystem
+  path.
 - The repository has one `dev.sqlcj.runtime.QueryExecutor` field and one
   constructor taking that executor.
 - Methods appear in query-source order. A method name is the lower camel form
@@ -351,6 +355,8 @@ The `Author` entry of the [Quickstart](quickstart.md), which declares
 `DeleteAuthor`, generates one `AuthorRepository`:
 
 ```java
+// Code generated by sqlcj. DO NOT EDIT.
+
 package com.example.app.db;
 
 import dev.sqlcj.runtime.QueryExecutor;
diff --git a/sqlcj-cli/src/main/java/dev/sqlcj/generator/JavaCodeGenerator.java b/sqlcj-cli/src/main/java/dev/sqlcj/generator/JavaCodeGenerator.java
index c3d2d4e..ac4a0ae 100644
--- a/sqlcj-cli/src/main/java/dev/sqlcj/generator/JavaCodeGenerator.java
+++ b/sqlcj-cli/src/main/java/dev/sqlcj/generator/JavaCodeGenerator.java
@@ -25,6 +25,8 @@ public final class JavaCodeGenerator implements CodeGenerator {
 
     private static final String DEFAULT_PACKAGE = "generated";
 
+    private static final String GENERATED_NOTICE = "// Code generated by sqlcj. DO NOT EDIT.";
+
     private final TypeResolver typeResolver = new DefaultTypeResolver();
     private final String packageName;
 
@@ -71,9 +73,12 @@ private String generateSource(QueryGroupModel group, JavaNames names) {
 
             %s
 
+            %s
+
             %s
             """
             .formatted(
+                GENERATED_NOTICE,
                 generatePackage(),
                 generateImports(group),
                 generateRepositoryJavaDoc(group).stripTrailing(),
diff --git a/sqlcj-cli/src/test/java/dev/sqlcj/cli/command/GenerateCommandTest.java b/sqlcj-cli/src/test/java/dev/sqlcj/cli/command/GenerateCommandTest.java
index cb6f8b6..138b8d7 100644
--- a/sqlcj-cli/src/test/java/dev/sqlcj/cli/command/GenerateCommandTest.java
+++ b/sqlcj-cli/src/test/java/dev/sqlcj/cli/command/GenerateCommandTest.java
@@ -68,7 +68,11 @@ void shouldGenerateFromConfigurationInWorkingDirectory() throws Exception {
 
         String source = Files.readString(generated);
 
-        assertTrue(source.startsWith("package dev.example.generated;"));
+        assertTrue(
+            source.startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage dev.example.generated;"
+            )
+        );
         assertTrue(source.contains("public final class UsersRepository {"));
         assertTrue(source.contains("public GetUserResult getUser(Long id)"));
     }
diff --git a/sqlcj-cli/src/test/java/dev/sqlcj/compiler/SqlcjCompilerIntegrationTest.java b/sqlcj-cli/src/test/java/dev/sqlcj/compiler/SqlcjCompilerIntegrationTest.java
index fffde51..ee6bbdf 100644
--- a/sqlcj-cli/src/test/java/dev/sqlcj/compiler/SqlcjCompilerIntegrationTest.java
+++ b/sqlcj-cli/src/test/java/dev/sqlcj/compiler/SqlcjCompilerIntegrationTest.java
@@ -1237,13 +1237,21 @@ total      DECIMAL(10, 2),
 
         String users = Files.readString(usersFile);
 
-        assertTrue(users.startsWith("package dev.example.generated;"));
+        assertTrue(
+            users.startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage dev.example.generated;"
+            )
+        );
         assertTrue(users.contains("public final class UsersRepository {"));
         assertTrue(users.contains("public GetUserResult getUser(Long id)"));
 
         String orders = Files.readString(ordersFile);
 
-        assertTrue(orders.startsWith("package dev.example.generated;"));
+        assertTrue(
+            orders.startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage dev.example.generated;"
+            )
+        );
         assertTrue(orders.contains("public final class OrdersRepository {"));
         assertTrue(orders.contains("public List<ListOrdersResult> listOrders(LocalDateTime createdAt)"));
         assertTrue(orders.contains("BigDecimal total"));
diff --git a/sqlcj-cli/src/test/java/dev/sqlcj/generator/JavaCodeGeneratorTest.java b/sqlcj-cli/src/test/java/dev/sqlcj/generator/JavaCodeGeneratorTest.java
index 7b84b20..0b8286e 100644
--- a/sqlcj-cli/src/test/java/dev/sqlcj/generator/JavaCodeGeneratorTest.java
+++ b/sqlcj-cli/src/test/java/dev/sqlcj/generator/JavaCodeGeneratorTest.java
@@ -180,10 +180,43 @@ void shouldGeneratePackageDeclaration() {
         );
 
         assertTrue(
-            file.content().startsWith("package generated;")
+            file.content().startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage generated;"
+            )
         );
     }
 
+    @Test
+    void shouldGenerateDoNotEditNoticeBeforePackageDeclaration() {
+        CodeGenerator generator = new JavaCodeGenerator("dev.example.generated");
+
+        GeneratedFile file = generate(
+            generator,
+            query(
+                "GetUser",
+                QueryType.ONE,
+                List.of(
+                    new QueryParameter(1, "id", ColumnType.BIGINT)
+                )
+            )
+        );
+
+        String source = file.content();
+
+        assertTrue(
+            source.startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage dev.example.generated;\n"
+            )
+        );
+
+        assertEquals(
+            1,
+            source.split("// Code generated by sqlcj\\. DO NOT EDIT\\.", -1).length - 1
+        );
+
+        assertTrue(source.contains(" * Generated by sqlcj."));
+    }
+
     @Test
     void shouldGenerateConfiguredPackageDeclarationAndPath() throws IOException {
         CodeGenerator generator = new JavaCodeGenerator("dev.example.generated");
@@ -211,7 +244,9 @@ void shouldGenerateConfiguredPackageDeclarationAndPath() throws IOException {
         );
 
         assertTrue(
-            file.content().startsWith("package dev.example.generated;")
+            file.content().startsWith(
+                "// Code generated by sqlcj. DO NOT EDIT.\n\npackage dev.example.generated;"
+            )
         );
 
         assertCompiles(file);