diff --git a/pkgs/development/compilers/vala/default.nix b/pkgs/development/compilers/vala/default.nix
index 5f21399229a..d94437b6a16 100644
--- a/pkgs/development/compilers/vala/default.nix
+++ b/pkgs/development/compilers/vala/default.nix
@@ -1,5 +1,5 @@
 { stdenv, lib, fetchurl, fetchpatch, pkgconfig, flex, bison, libxslt, autoconf, automake, autoreconfHook
-, graphviz, glib, libiconv, libintl, libtool, expat
+, graphviz, glib, libiconv, libintl, libtool, expat, substituteAll
 }:
 
 let
@@ -45,6 +45,11 @@ let
     name = "vala-${version}";
     version = "${major}.${minor}";
 
+    setupHook = substituteAll {
+      src = ./setup-hook.sh;
+      apiVersion = major;
+    };
+
     src = fetchurl {
       url = "mirror://gnome/sources/vala/${major}/${name}.tar.xz";
       inherit sha256;
diff --git a/pkgs/development/compilers/vala/setup-hook.sh b/pkgs/development/compilers/vala/setup-hook.sh
new file mode 100644
index 00000000000..8252143e998
--- /dev/null
+++ b/pkgs/development/compilers/vala/setup-hook.sh
@@ -0,0 +1,15 @@
+make_vala_find_vapi_files() {
+    # XDG_DATA_DIRS: required for finding .vapi files
+    if [ -d "$1/share/vala/vapi" -o -d "$1/share/vala-@apiVersion@/vapi" ]; then
+      addToSearchPath XDG_DATA_DIRS $1/share
+    fi
+}
+
+addEnvHooks "$hostOffset" make_vala_find_vapi_files
+
+_multioutMoveVapiDirs() {
+  moveToOutput share/vala/vapi "${!outputDev}"
+  moveToOutput share/vala-@apiVersion@/vapi "${!outputDev}"
+}
+
+preFixupHooks+=(_multioutMoveVapiDirs)
diff --git a/pkgs/development/libraries/gobject-introspection/setup-hook.sh b/pkgs/development/libraries/gobject-introspection/setup-hook.sh
index a79ce05a38d..a68d544cfbe 100644
--- a/pkgs/development/libraries/gobject-introspection/setup-hook.sh
+++ b/pkgs/development/libraries/gobject-introspection/setup-hook.sh
@@ -4,8 +4,8 @@ make_gobject_introspection_find_gir_files() {
       addToSearchPath GI_TYPELIB_PATH $1/lib/girepository-1.0
     fi
 
-    # XDG_DATA_DIRS: required for .gir files?
-    if [ -d "$1/share" ]; then
+    # XDG_DATA_DIRS: required for finding .gir files
+    if [ -d "$1/share/gir-1.0" ]; then
       addToSearchPath XDG_DATA_DIRS $1/share
     fi
 }