diff --git a/mercurial/extensions.py b/mercurial/extensions.py
--- a/mercurial/extensions.py
+++ b/mercurial/extensions.py
@@ -101,6 +101,17 @@ def load(ui, name, path):
             if ui.debugflag:
                 ui.traceback()
             mod = importh(name)
+
+    # Before we do anything with the extension, check against minimum stated
+    # compatibility. This gives extension authors a mechanism to have their
+    # extensions short circuit when loaded with a known incompatible version
+    # of Mercurial.
+    minver = getattr(mod, 'minimumhgversion', None)
+    if minver and util.versiontuple(minver, 2) > util.versiontuple(n=2):
+        ui.warn(_('(third party extension %s requires version %s or newer '
+                  'of Mercurial; disabling)\n') % (shortname, minver))
+        return
+
     _extensions[shortname] = mod
     _order.append(shortname)
     for fn in _aftercallbacks.get(shortname, []):
diff --git a/tests/test-extension.t b/tests/test-extension.t
--- a/tests/test-extension.t
+++ b/tests/test-extension.t
@@ -1009,6 +1009,50 @@ Test version number support in 'hg versi
   
     throw  1.twentythree
 
+Refuse to load extensions with minimum version requirements
+
+  $ cat > minversion1.py << EOF
+  > from mercurial import util
+  > util.version = lambda: '3.5.2'
+  > minimumhgversion = '3.6'
+  > EOF
+  $ hg --config extensions.minversion=minversion1.py version
+  (third party extension minversion requires version 3.6 or newer of Mercurial; disabling)
+  Mercurial Distributed SCM (version 3.5.2)
+  (see https://mercurial-scm.org for more information)
+  
+  Copyright (C) 2005-* Matt Mackall and others (glob)
+  This is free software; see the source for copying conditions. There is NO
+  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+  $ cat > minversion2.py << EOF
+  > from mercurial import util
+  > util.version = lambda: '3.6'
+  > minimumhgversion = '3.7'
+  > EOF
+  $ hg --config extensions.minversion=minversion2.py version 2>&1 | egrep '\(third'
+  (third party extension minversion requires version 3.7 or newer of Mercurial; disabling)
+
+Can load version that is only off by point release
+
+  $ cat > minversion2.py << EOF
+  > from mercurial import util
+  > util.version = lambda: '3.6.1'
+  > minimumhgversion = '3.6'
+  > EOF
+  $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
+  [1]
+
+Can load minimum version identical to current
+
+  $ cat > minversion3.py << EOF
+  > from mercurial import util
+  > util.version = lambda: '3.5'
+  > minimumhgversion = '3.5'
+  > EOF
+  $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
+  [1]
+
 Restore HGRCPATH
 
   $ HGRCPATH=$ORGHGRCPATH