Wireless mesh networks (WMNs) have recently evoked much research attention as a novel technology for last-mile broadband Internet access. When designing a WMN, gateway placement is significant for it determines the total network throughput. To address this problem, a novel gateway placement approach is proposed in this paper, in which three objectives are optimized, i.e. the number of gateways, the average MR (mesh router)-GW (gateway) hop count and the variance of gateway load. The gateway placement problem is modeled as a multiple objective linear program first, and then a two-stage load balanced gateway placement algorithm is proposed. The first stage is weight-based greedy gateway selection, and the second stage is load balanced MR attachment. Simulation results show that the algorithm behaves similarly compared with existing approaches in both number of gateways and average MR-GW hop count, while achieving better load balance.