diff --git a/src/network/networkpacket.cpp b/src/network/networkpacket.cpp
index 91e6c58e..f7a6499d 100644
--- a/src/network/networkpacket.cpp
+++ b/src/network/networkpacket.cpp
@@ -105,7 +105,7 @@ NetworkPacket& NetworkPacket::operator>>(std::string& dst)
 	return *this;
 }
 
-NetworkPacket& NetworkPacket::operator<<(std::string src)
+NetworkPacket& NetworkPacket::operator<<(const std::string &src)
 {
 	u16 msgsize = src.size();
 	if (msgsize > STRING_MAX_LEN) {
@@ -119,7 +119,7 @@ NetworkPacket& NetworkPacket::operator<<(std::string src)
 	return *this;
 }
 
-void NetworkPacket::putLongString(std::string src)
+void NetworkPacket::putLongString(const std::string &src)
 {
 	u32 msgsize = src.size();
 	if (msgsize > LONG_STRING_MAX_LEN) {
@@ -155,7 +155,7 @@ NetworkPacket& NetworkPacket::operator>>(std::wstring& dst)
 	return *this;
 }
 
-NetworkPacket& NetworkPacket::operator<<(std::wstring src)
+NetworkPacket& NetworkPacket::operator<<(const std::wstring &src)
 {
 	u16 msgsize = src.size();
 	if (msgsize > WIDE_STRING_MAX_LEN) {
diff --git a/src/network/networkpacket.h b/src/network/networkpacket.h
index 3e436aba..83dc33f6 100644
--- a/src/network/networkpacket.h
+++ b/src/network/networkpacket.h
@@ -52,12 +52,12 @@ public:
 			{ putRawString(src.c_str(), src.size()); }
 
 		NetworkPacket& operator>>(std::string& dst);
-		NetworkPacket& operator<<(std::string src);
+		NetworkPacket& operator<<(const std::string &src);
 
-		void putLongString(std::string src);
+		void putLongString(const std::string &src);
 
 		NetworkPacket& operator>>(std::wstring& dst);
-		NetworkPacket& operator<<(std::wstring src);
+		NetworkPacket& operator<<(const std::wstring &src);
 
 		std::string readLongString();