diff --git a/PROTOCOL.md b/PROTOCOL.md
index 308c628d..a7724270 100644
--- a/PROTOCOL.md
+++ b/PROTOCOL.md
@@ -33,6 +33,10 @@ Currently this is to be handled by TLS.
 
 This entire protocol is built to be layered on top of TCP or TLS.
 
+### Byte Order
+
+All numeric values are in network (big-endian) byte order.
+
 ### Framing
 
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