We propose an interference-aware user selection scheme for uplink multiuser multiple-input multiple-output (MU-MIMO) systems in a multicell environment. The proposed scheme works in a distributed manner. Each mobile station (MS) determines its transmit beamforming vector based on the locally available channel state information (CSI), and informs the associated base station (BS) of the amount of potential interference caused to adjacent cells along with the resulting beamforming vector. Then, the BS selects a set of users to be served simultaneously with consideration of intercell interference. The user selection scheme is devised either to maximize the sum rate or to achieve proportional fairness among users. For each case, we derive an optimal user selection criterion and propose a suboptimal distributed user selection algorithm with low complexity. Simulation results confirm that the proposed scheme offers significant throughput enhancement due to reduction of the intercell interference in a multicell environment.