diff --git a/pkgs/development/interpreters/guile/2.0.nix b/pkgs/development/interpreters/guile/2.0.nix
index 73fb564077a3..9e2953aa2f9e 100644
--- a/pkgs/development/interpreters/guile/2.0.nix
+++ b/pkgs/development/interpreters/guile/2.0.nix
@@ -120,7 +120,7 @@ builder rec {
   + ''
     sed -i "$out/lib/pkgconfig/guile"-*.pc    \
         -e "s|-lunistring|-L${libunistring}/lib -lunistring|g ;
-            s|^Cflags:\(.*\)$|Cflags: -I${libunistring}/include \1|g ;
+            s|^Cflags:\(.*\)$|Cflags: -I${libunistring.dev}/include \1|g ;
             s|-lltdl|-L${libtool.lib}/lib -lltdl|g ;
             s|includedir=$out|includedir=$dev|g
             "
diff --git a/pkgs/development/interpreters/guile/2.2.nix b/pkgs/development/interpreters/guile/2.2.nix
index 31803d9c1665..c101f5ae3903 100644
--- a/pkgs/development/interpreters/guile/2.2.nix
+++ b/pkgs/development/interpreters/guile/2.2.nix
@@ -111,7 +111,7 @@ builder rec {
   + ''
     sed -i "$out/lib/pkgconfig/guile"-*.pc    \
         -e "s|-lunistring|-L${libunistring}/lib -lunistring|g ;
-            s|^Cflags:\(.*\)$|Cflags: -I${libunistring}/include \1|g ;
+            s|^Cflags:\(.*\)$|Cflags: -I${libunistring.dev}/include \1|g ;
             s|-lltdl|-L${libtool.lib}/lib -lltdl|g ;
             s|includedir=$out|includedir=$dev|g
             "
diff --git a/pkgs/development/interpreters/guile/3.0.nix b/pkgs/development/interpreters/guile/3.0.nix
index b7ad4e4ec727..ced8561720d3 100644
--- a/pkgs/development/interpreters/guile/3.0.nix
+++ b/pkgs/development/interpreters/guile/3.0.nix
@@ -114,7 +114,7 @@ builder rec {
   + ''
     sed -i "$out/lib/pkgconfig/guile"-*.pc    \
         -e "s|-lunistring|-L${libunistring}/lib -lunistring|g ;
-            s|^Cflags:\(.*\)$|Cflags: -I${libunistring}/include \1|g ;
+            s|^Cflags:\(.*\)$|Cflags: -I${libunistring.dev}/include \1|g ;
             s|-lltdl|-L${libtool.lib}/lib -lltdl|g ;
             s|includedir=$out|includedir=$dev|g
             "