diff --git a/lib/spack/spack/cmd/diy.py b/lib/spack/spack/cmd/diy.py
index 5a8ec255e2ea44..1e5de1b7b99a2b 100644
--- a/lib/spack/spack/cmd/diy.py
+++ b/lib/spack/spack/cmd/diy.py
@@ -38,6 +38,9 @@
 
 
 def setup_parser(subparser):
+    subparser.add_argument(
+        '-j', '--jobs', action='store', type=int,
+        help="Explicitly set number of make jobs.  Default is #cpus.")
     subparser.add_argument(
         '-d', '--source-path', dest='source_path',
         help="Path to the source directory. Defaults to the current directory")
@@ -65,6 +68,10 @@ def diy(self, args):
     if not args.spec:
         tty.die("spack diy requires a package spec argument.")
 
+    if args.jobs is not None:
+        if args.jobs <= 0:
+            tty.die("The -j option must be a positive integer!")
+
     specs = spack.cmd.parse_specs(args.spec)
     if len(specs) > 1:
         tty.die("spack diy only takes one spec.")
@@ -108,6 +115,7 @@ def diy(self, args):
     spack.do_checksum = False
 
     package.do_install(
+        make_jobs=args.jobs,
         keep_prefix=args.keep_prefix,
         install_deps=not args.ignore_deps,
         verbose=not args.quiet,