An access point can include an array of antennas and a smart antenna selector. The smart antenna selector is configured to select a subset of antennas from the antenna array for use in multi-user multiple-input multiple-output (MU MIMO) data transmissions. Stations that are communicatively coupled to the access point can be selected for inclusion in a multi-user group based, at least in part, on performance measurements of the stations. Performance measurements are determined directly and indirectly from data transmissions sent in response to sounding packets. Antennas for use in MU MIMO data transmissions are selected for the antenna array based, at least in part, on previous antenna selections used for single user data transmissions.