diff --git a/mesonpy/_rpath.py b/mesonpy/_rpath.py
index 65039c665..c0aea7659 100644
--- a/mesonpy/_rpath.py
+++ b/mesonpy/_rpath.py
@@ -37,7 +37,7 @@ def fix_rpath(cls, filepath: Path, install_rpath: list[str], build_rpath: list[s
         old_rpath = cls.get_rpath(filepath)
 
         # Prepend install_rpath entries.
-        new_rpath = install_rpath
+        new_rpath = install_rpath[:]
 
         # Merge with existing entries, excluding build_rpath entries.  Meson
         # adds a padding entry to RPATH composed of enough ``X`` characters