diff --git a/pkgs/development/r-modules/default.nix b/pkgs/development/r-modules/default.nix
index ffe277582392d..0b0587b4ba347 100644
--- a/pkgs/development/r-modules/default.nix
+++ b/pkgs/development/r-modules/default.nix
@@ -362,7 +362,7 @@ let
     mwaved = [ pkgs.fftw.dev ];
     mzR = with pkgs; [ zlib boost159.dev netcdf ];
     ncdf4 = [ pkgs.netcdf ];
-    nloptr = with pkgs; [ nlopt pkg-config ];
+    nloptr = with pkgs; [ nlopt pkg-config libiconv ];
     n1qn1 = [ pkgs.gfortran ];
     odbc = [ pkgs.unixODBC ];
     pander = with pkgs; [ pandoc which ];