diff --git a/var/spack/repos/builtin/packages/lcals/package.py b/var/spack/repos/builtin/packages/lcals/package.py
index 9305c3dcb3..e5a39b5a05 100644
--- a/var/spack/repos/builtin/packages/lcals/package.py
+++ b/var/spack/repos/builtin/packages/lcals/package.py
@@ -46,6 +46,8 @@ def build_targets(self):
             arch = 'MIC'
         elif arch == 'x86_64' or arch == 'x86_32':
             arch = 'x86'
+        elif arch == 'aarch64':
+            arch = 'aarch64'
         else:
             raise InstallError('unknown architecture.')
 
@@ -72,6 +74,10 @@ def build_targets(self):
                 cxxflags += '-DLCALS_PLATFORM_X86_AVX -DLCALS_COMPILER_GNU '
                 cxx_compile += '-Ofast -mavx -finline-functions'
                 ' -finline-limit=10000 -std=c++11'
+            elif arch == 'aarch64':
+                cxxflags += '-DLCALS_COMPILER_GNU '
+                cxx_compile += '-Ofast -finline-functions'
+                ' -finline-limit=10000 -std=c++11'
             cxxflags += self.compiler.openmp_flag
 
         targets.append('LCALS_ARCH=')