diff --git a/pkgs/development/r-modules/default.nix b/pkgs/development/r-modules/default.nix
index 5fb3813e3992..bedcb83ebd1d 100644
--- a/pkgs/development/r-modules/default.nix
+++ b/pkgs/development/r-modules/default.nix
@@ -500,6 +500,7 @@ let
     # sort -t '=' -k 2
     deldir = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];
     gam = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];
+    interp = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];
     RcppArmadillo = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];
     quantreg = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];
     rmutil = lib.optionals stdenv.isDarwin [ pkgs.libiconv ];