diff --git a/downstream.go b/downstream.go
index f48653e..0c02201 100644
--- a/downstream.go
+++ b/downstream.go
@@ -2230,6 +2230,23 @@ func (dc *downstreamConn) handleMessageRegistered(ctx context.Context, msg *irc.
 				}
 				if uc.isChannel(mask) {
 					info.Channel = mask
+
+					// Set channel membership prefixes from cached NAMES reply
+					ch := uc.channels.Get(info.Channel)
+					memberships := ch.Members.Get(info.Nickname)
+					prefixes := formatMemberPrefix(*memberships, dc)
+
+					// Channel membership prefixes are listed after away status ('G'/'H')
+					// and optional server operator indicator ('*')
+					i := strings.IndexFunc(info.Flags, func(f rune) bool {
+						return f != 'G' && f != 'H' && f != '*'
+					})
+
+					if i == -1 {
+						info.Flags = prefixes + info.Flags
+					} else {
+						info.Flags = info.Flags[:i] + prefixes + info.Flags[i:]
+					}
 				}
 				dc.SendMessage(ctx, xirc.GenerateWHOXReply(fields, &info))
 			}
diff --git a/irc.go b/irc.go
index 12732c4..9a7735b 100644
--- a/irc.go
+++ b/irc.go
@@ -194,6 +194,19 @@ func formatMemberPrefix(ms xirc.MembershipSet, dc *downstreamConn) string {
 	return string(prefixes)
 }
 
+// Remove channel membership prefixes from flags
+func stripMemberPrefixes(flags string, uc *upstreamConn) string {
+	return strings.Map(func(r rune) rune {
+		for _, v := range uc.availableMemberships {
+			if byte(r) == v.Prefix {
+				return -1
+			}
+		}
+
+		return r
+	}, flags)
+}
+
 func parseMessageParams(msg *irc.Message, out ...*string) error {
 	if len(msg.Params) < len(out) {
 		return newNeedMoreParamsError(msg.Command)
diff --git a/upstream.go b/upstream.go
index 9173c3a..025646e 100644
--- a/upstream.go
+++ b/upstream.go
@@ -1541,7 +1541,7 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 				Hostname: host,
 				Server:   server,
 				Nickname: nick,
-				Flags:    flags,
+				Flags:    stripMemberPrefixes(flags, uc),
 				Realname: realname,
 			})
 		}
@@ -1564,13 +1564,14 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 			if err != nil {
 				return err
 			}
+
 			if uc.shouldCacheUserInfo(info.Nickname) {
 				uc.cacheUserInfo(info.Nickname, &upstreamUser{
 					Nickname: info.Nickname,
 					Username: info.Username,
 					Hostname: info.Hostname,
 					Server:   info.Server,
-					Flags:    info.Flags,
+					Flags:    stripMemberPrefixes(info.Flags, uc),
 					Account:  info.Account,
 					Realname: info.Realname,
 				})