diff --git a/cpp/ql/lib/Customizations.qll b/cpp/ql/lib/Customizations.qll
new file mode 100644
index 000000000000..c9d899e07e01
--- /dev/null
+++ b/cpp/ql/lib/Customizations.qll
@@ -0,0 +1,11 @@
+/**
+ * Contains customizations to the standard library.
+ *
+ * This module is imported by `cpp.qll`, so any customizations defined here automatically
+ * apply to all queries.
+ *
+ * Typical examples of customizations include adding new subclasses of abstract classes such as
+ * the `RemoteFlowSource` class to model frameworks that are not covered by the standard library.
+ */
+
+import cpp
diff --git a/cpp/ql/lib/cpp.qll b/cpp/ql/lib/cpp.qll
index ccd32c368e4b..c8afac1c7ae9 100644
--- a/cpp/ql/lib/cpp.qll
+++ b/cpp/ql/lib/cpp.qll
@@ -13,6 +13,7 @@
  *     https://github.com/cplusplus/draft/raw/master/papers/n4140.pdf
  */
 
+import Customizations
 import semmle.code.cpp.File
 import semmle.code.cpp.Linkage
 import semmle.code.cpp.Location
diff --git a/cpp/ql/src/change-notes/2025-08-20-add-customizations.md b/cpp/ql/src/change-notes/2025-08-20-add-customizations.md
new file mode 100644
index 000000000000..3a01298283ca
--- /dev/null
+++ b/cpp/ql/src/change-notes/2025-08-20-add-customizations.md
@@ -0,0 +1,4 @@
+---
+category: fix
+---
+* Fixed an inconsistency across languages where most have a `Customizations.qll` file for adding customizations, but not all did.
\ No newline at end of file
diff --git a/rust/ql/lib/Customizations.qll b/rust/ql/lib/Customizations.qll
new file mode 100644
index 000000000000..8fc6bbea9116
--- /dev/null
+++ b/rust/ql/lib/Customizations.qll
@@ -0,0 +1,11 @@
+/**
+ * Contains customizations to the standard library.
+ *
+ * This module is imported by `rust.qll`, so any customizations defined here automatically
+ * apply to all queries.
+ *
+ * Typical examples of customizations include adding new subclasses of abstract classes such as
+ * the `RemoteFlowSource` class to model frameworks that are not covered by the standard library.
+ */
+
+import rust
diff --git a/rust/ql/lib/rust.qll b/rust/ql/lib/rust.qll
index e7d02adea32b..b46e96868f63 100644
--- a/rust/ql/lib/rust.qll
+++ b/rust/ql/lib/rust.qll
@@ -1,5 +1,6 @@
 /** Top-level import for the Rust language pack */
 
+import Customizations
 import codeql.rust.elements
 import codeql.Locations
 import codeql.files.FileSystem
diff --git a/rust/ql/src/change-notes/2025-08-20-add-customizations.md b/rust/ql/src/change-notes/2025-08-20-add-customizations.md
new file mode 100644
index 000000000000..3a01298283ca
--- /dev/null
+++ b/rust/ql/src/change-notes/2025-08-20-add-customizations.md
@@ -0,0 +1,4 @@
+---
+category: fix
+---
+* Fixed an inconsistency across languages where most have a `Customizations.qll` file for adding customizations, but not all did.
\ No newline at end of file
diff --git a/swift/ql/lib/Customizations.qll b/swift/ql/lib/Customizations.qll
new file mode 100644
index 000000000000..bf9e66de70b8
--- /dev/null
+++ b/swift/ql/lib/Customizations.qll
@@ -0,0 +1,11 @@
+/**
+ * Contains customizations to the standard library.
+ *
+ * This module is imported by `swift.qll`, so any customizations defined here automatically
+ * apply to all queries.
+ *
+ * Typical examples of customizations include adding new subclasses of abstract classes such as
+ * the `RemoteFlowSource` class to model frameworks that are not covered by the standard library.
+ */
+
+import swift
diff --git a/swift/ql/lib/swift.qll b/swift/ql/lib/swift.qll
index 901d9e895e02..54f2abf90925 100644
--- a/swift/ql/lib/swift.qll
+++ b/swift/ql/lib/swift.qll
@@ -1,5 +1,6 @@
 /** Top-level import for the Swift language pack */
 
+import Customizations
 import codeql.swift.elements
 import codeql.swift.elements.expr.ArithmeticOperation
 import codeql.swift.elements.expr.Assignment
diff --git a/swift/ql/src/change-notes/2025-08-20-add-customizations.md b/swift/ql/src/change-notes/2025-08-20-add-customizations.md
new file mode 100644
index 000000000000..3a01298283ca
--- /dev/null
+++ b/swift/ql/src/change-notes/2025-08-20-add-customizations.md
@@ -0,0 +1,4 @@
+---
+category: fix
+---
+* Fixed an inconsistency across languages where most have a `Customizations.qll` file for adding customizations, but not all did.
\ No newline at end of file