diff --git a/schema.yaml b/schema.yaml
index a4d3aee..f82f8de 100644
--- a/schema.yaml
+++ b/schema.yaml
@@ -7,14 +7,16 @@ bondethernet:
 ---
 interface:
   description: str(exclude='\'"',required=False)
-  lcp: str(max=8,matches='[a-z]+[a-z0-9-]{,7}',required=False)
   mac: mac(required=False)
+  lcp: str(max=8,matches='[a-z]+[a-z0-9-]{,7}',required=False)
+  mtu: int(min=128,max=9216,required=False)
   addresses: list(ip_interface(),min=1,max=6,required=False)
   sub-interfaces: map(include('sub-interface'),key=int(min=1,max=4294967295),required=False)
 ---
 sub-interface:
   description: str(exclude='\'"',required=False)
   lcp: str(max=8,matches='[a-z]+[a-z0-9-]{,7}',required=False)
+  mtu: int(min=128,max=9216,required=False)
   addresses: list(ip_interface(),required=False)
   encapsulation: include('encapsulation',required=False)
 ---
@@ -23,4 +25,3 @@ encapsulation:
   dot1ad: int(min=1,max=4095,required=False)
   inner-dot1q: int(min=1,max=4095,required=False)
   exact-match: bool(required=False)
-
diff --git a/validator/interface.py b/validator/interface.py
index b7c0e96..992c6fb 100644
--- a/validator/interface.py
+++ b/validator/interface.py
@@ -121,6 +121,10 @@ def interface(args, yaml):
             msgs.append("interface %s does not exist in bondethernets" % ifname)
             result = False
 
+        if 'mtu' in iface:
+            iface_mtu = iface['mtu']
+        else:
+            iface_mtu = 1500
         iface_lcp = has_lcp(yaml, ifname)
         iface_address = has_address(yaml, ifname)
 
@@ -132,6 +136,10 @@ def interface(args, yaml):
             for sub_id, sub_iface in yaml['interfaces'][ifname]['sub-interfaces'].items():
                 sub_ifname = "%s.%d" % (ifname, sub_id)
                 logger.debug("sub-interface %s" % sub_iface)
+                if 'mtu' in sub_iface:
+                    if sub_iface['mtu'] > iface_mtu:
+                        msgs.append("sub-interface %s has MTU %d higher than parent MTU %d" % (sub_ifname, sub_iface['mtu'], iface_mtu))
+                        result = False
                 if has_lcp(yaml, sub_ifname):
                     if not iface_lcp:
                         msgs.append("sub-interface %s has LCP but %s does not have LCP" % (sub_ifname, ifname))