diff --git a/get_version.py b/get_version.py
index 759336d..9224f59 100644
--- a/get_version.py
+++ b/get_version.py
@@ -5,16 +5,19 @@ import os, subprocess, runpy
 os.chdir(os.path.split(os.path.abspath(__file__))[0])
 VERSIONFILE = os.path.join("hy", "version.py")
 
-try:
-    __version__ = (subprocess.check_output
-                   (["git", "describe", "--tags", "--dirty"])
-                   .decode('ASCII').strip()
-                   .replace('-', '+', 1).replace('-', '.'))
-    with open(VERSIONFILE, "wt") as o:
-        o.write("__version__ = {!r}\n".format(__version__))
+if "HY_VERSION" in os.environ:
+    __version__ = os.environ["HY_VERSION"]
+else:
+    try:
+        __version__ = (subprocess.check_output
+                       (["git", "describe", "--tags", "--dirty"])
+                       .decode('ASCII').strip()
+                       .replace('-', '+', 1).replace('-', '.'))
+        with open(VERSIONFILE, "wt") as o:
+            o.write("__version__ = {!r}\n".format(__version__))
 
-except (subprocess.CalledProcessError, OSError):
-    if os.path.exists(VERSIONFILE):
-        __version__ = runpy.run_path(VERSIONFILE)['__version__']
-    else:
-        __version__ = "unknown"
+    except (subprocess.CalledProcessError, OSError):
+        if os.path.exists(VERSIONFILE):
+            __version__ = runpy.run_path(VERSIONFILE)['__version__']
+        else:
+            __version__ = "unknown"