diff --git a/lib/spack/spack/compilers/clang.py b/lib/spack/spack/compilers/clang.py
index 8a60ebcaed..44de77af4f 100644
--- a/lib/spack/spack/compilers/clang.py
+++ b/lib/spack/spack/compilers/clang.py
@@ -47,6 +47,14 @@ class Clang(Compiler):
                    'f77' : 'f77',
                    'fc'  : 'f90' }
 
+    @property
+    def openmp_flag(self):
+        ver = '%s' % self.version
+        if ver.endswith('-apple'):
+            tty.die("Clang from Apple does not support Openmp yet.")
+        else:
+            return "-fopenmp"
+
     @property
     def cxx11_flag(self):
         if ver.endswith('-apple'):
diff --git a/lib/spack/spack/compilers/gcc.py b/lib/spack/spack/compilers/gcc.py
index 2e57e44856..91c498ac82 100644
--- a/lib/spack/spack/compilers/gcc.py
+++ b/lib/spack/spack/compilers/gcc.py
@@ -49,6 +49,10 @@ class Gcc(Compiler):
                   'f77' : 'gcc/gfortran',
                   'fc'  : 'gcc/gfortran' }
 
+    @property
+    def openmp_flag(self):
+        return "-fopenmp"
+
     @property
     def cxx11_flag(self):
         if self.version < ver('4.3'):
diff --git a/lib/spack/spack/compilers/intel.py b/lib/spack/spack/compilers/intel.py
index 69e9764790..f04a6aa899 100644
--- a/lib/spack/spack/compilers/intel.py
+++ b/lib/spack/spack/compilers/intel.py
@@ -43,6 +43,10 @@ class Intel(Compiler):
                    'f77' : 'intel/ifort',
                    'fc'  : 'intel/ifort' }
 
+    @property
+    def openmp_flag(self):
+        return "-openmp"
+
     @property
     def cxx11_flag(self):
         if self.version < ver('11.1'):
@@ -68,5 +72,3 @@ def default_version(cls, comp):
         """
         return get_compiler_version(
             comp, '--version', r'\((?:IFORT|ICC)\) ([^ ]+)')
-
-
diff --git a/lib/spack/spack/compilers/nag.py b/lib/spack/spack/compilers/nag.py
index 1df6b1c591..61486f22bd 100644
--- a/lib/spack/spack/compilers/nag.py
+++ b/lib/spack/spack/compilers/nag.py
@@ -20,6 +20,10 @@ class Nag(Compiler):
                    'f77' : 'nag/nagfor',
                    'fc'  : 'nag/nagfor' }
 
+    @property
+    def openmp_flag(self):
+        return "-openmp"
+
     @property
     def cxx11_flag(self):
         tty.die("cxx11_flag() is not implemented for nag. Consider creating a pull-request.")
diff --git a/lib/spack/spack/compilers/pgi.py b/lib/spack/spack/compilers/pgi.py
index ebf644404b..299b9a7016 100644
--- a/lib/spack/spack/compilers/pgi.py
+++ b/lib/spack/spack/compilers/pgi.py
@@ -43,6 +43,10 @@ class Pgi(Compiler):
                    'f77' : 'pgi/pgfortran',
                    'fc'  : 'pgi/pgfortran' }
 
+    @property
+    def openmp_flag(self):
+        return "-mp"
+
     @property
     def cxx11_flag(self):
         tty.die("cxx11_flag() is not implemented for pgi. Consider creating a pull-request.")
diff --git a/lib/spack/spack/compilers/xl.py b/lib/spack/spack/compilers/xl.py
index c1d55109a3..657309fe06 100644
--- a/lib/spack/spack/compilers/xl.py
+++ b/lib/spack/spack/compilers/xl.py
@@ -44,6 +44,10 @@ class Xl(Compiler):
                    'f77' : 'xl/xlf',
                    'fc'  : 'xl/xlf90' }
 
+    @property
+    def openmp_flag(self):
+        return "-qsmp=omp"
+
     @property
     def cxx11_flag(self):
         if self.version < ver('13.1'):