diff --git a/lib/spack/spack/architecture.py b/lib/spack/spack/architecture.py
index c67b63cba00..53cbc44ca53 100644
--- a/lib/spack/spack/architecture.py
+++ b/lib/spack/spack/architecture.py
@@ -493,3 +493,15 @@ def sys_type():
     """
     arch = Arch(platform(), 'default_os', 'default_target')
     return str(arch)
+
+
+@memoized
+def compatible_sys_types():
+    """Returns a list of all the systypes compatible with the current host."""
+    compatible_archs = []
+    current_host = cpu.host()
+    compatible_targets = [current_host] + current_host.ancestors
+    for target in compatible_targets:
+        arch = Arch(platform(), 'default_os', target)
+        compatible_archs.append(str(arch))
+    return compatible_archs
diff --git a/lib/spack/spack/main.py b/lib/spack/spack/main.py
index a2220a9ba81..c3746b6b26a 100644
--- a/lib/spack/spack/main.py
+++ b/lib/spack/spack/main.py
@@ -585,7 +585,8 @@ def shell_set(var, value):
 
     # print sys type
     shell_set('_sp_sys_type', spack.architecture.sys_type())
-
+    shell_set('_sp_compatible_sys_types',
+              ':'.join(spack.architecture.compatible_sys_types()))
     # print roots for all module systems
     module_roots = spack.config.get('config:module_roots')
     module_to_roots = {
diff --git a/share/spack/setup-env.csh b/share/spack/setup-env.csh
index f2b5b00006f..ac5479196d4 100755
--- a/share/spack/setup-env.csh
+++ b/share/spack/setup-env.csh
@@ -26,8 +26,11 @@ if ($?SPACK_ROOT) then
 
     # Set up modules and dotkit search paths in the user environment
     set tcl_roots = `echo $_sp_tcl_roots:q | sed 's/:/ /g'`
+    set compatible_sys_types = `echo $_sp_compatible_sys_types:q | sed 's/:/ /g'`
     foreach tcl_root ($tcl_roots:q)
-        _spack_pathadd MODULEPATH "$tcl_root/$_sp_sys_type"
+        foreach systype ($compatible_sys_types:q)
+            _spack_pathadd MODULEPATH "$tcl_root/$systype"
+        end
     end
 
     set dotkit_roots = `echo $_sp_dotkit_roots:q | sed 's/:/ /g'`
diff --git a/share/spack/setup-env.sh b/share/spack/setup-env.sh
index ae6d00a47b7..0fd5eb30f72 100755
--- a/share/spack/setup-env.sh
+++ b/share/spack/setup-env.sh
@@ -350,7 +350,9 @@ _sp_multi_pathadd() {
         setopt sh_word_split
     fi
     for pth in $2; do
-        _spack_pathadd "$1" "${pth}/${_sp_sys_type}"
+        for systype in ${_sp_compatible_sys_types}; do
+            _spack_pathadd "$1" "${pth}/${systype}"
+        done
     done
 }
 _sp_multi_pathadd MODULEPATH "$_sp_tcl_roots"