diff --git a/lib/spack/spack/cmd/spec.py b/lib/spack/spack/cmd/spec.py
index f63ac638c4d77e8725cfaeb2d34c6a3ed06d86f5..2ab7228c41e849fb93bc29dede5db69bbf2a3cd3 100644
--- a/lib/spack/spack/cmd/spec.py
+++ b/lib/spack/spack/cmd/spec.py
@@ -9,6 +9,7 @@
 import sys
 
 import llnl.util.tty as tty
+import llnl.util.tty.color as color
 
 import spack
 import spack.cmd
@@ -37,6 +38,9 @@ def setup_parser(subparser):
     subparser.add_argument(
         '-N', '--namespaces', action='store_true', default=False,
         help='show fully qualified package names')
+    subparser.add_argument(
+        '-u', '--uarch-flags', action='store_true', default=False,
+        help='show microarchitecture optimization flags')
 
     subparser.add_argument(
         '-t', '--types', action='store_true', default=False,
@@ -49,6 +53,7 @@ def spec(parser, args):
     name_fmt = '{namespace}.{name}' if args.namespaces else '{name}'
     fmt = '{@version}{%compiler}{compiler_flags}{variants}{arch=architecture}'
     install_status_fn = spack.spec.Spec.install_status
+
     kwargs = {
         'cover': args.cover,
         'format': name_fmt + fmt,
@@ -79,6 +84,11 @@ def spec(parser, args):
         print(spec.tree(**kwargs))
 
         kwargs['hashes'] = args.long or args.very_long
+        if args.uarch_flags:
+            kwargs["format"] += color.colorize(
+                " @Kuarch_flags=\"{uarch_flags}\"@."
+            )
+
         print("Concretized")
         print("--------------------------------")
         spec.concretize()
diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index 3cda07ec482aab3f33465d2c74159cd450c5fedc..6215a9d1aec4bb61b8de7b767cd2f9918947c2ad 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -1053,7 +1053,7 @@ function _spack_spec {
     then
         compgen -W "-h --help -l --long -L --very-long -I --install-status
                     -j --json -y --yaml -c --cover -N --namespaces
-                    -t --types" -- "$cur"
+                    -t --types -u --uarch-flags" -- "$cur"
     else
         compgen -W "$(_all_packages)" -- "$cur"
     fi