In this study, routing protocols for wireless mesh networks have been investigated in terms of scalability and a scalability routing protocol has been developed for wireless mesh networks. Developed protocol, Ad-hoc on Demand Scalable Routing Protocol (ADSRP), has been activated whenever it needs to find a route. The protocol prevents packet loss due to scalability in network. Moreover, it needs less routing overhead than the others. It does not need unnecessary route request packets using heuristic route. The protocol enables scalability of network with low cost. ADSRP has been tested using ns-2 simulation tool and experimental results have been compared with Ad-hoc On Demand Distance Vector (AODV) and Ad-hoc On Demand Multipath Distance Vector (AOMDV) protocols extensively. Obtained results show that the developed protocol is successful for wireless mesh networks.