An approach for inter-gateway interference estimation and admission control is provided. A gateway receives return link signals, each being received via a satellite from a respective user terminal (UT) located within a satellite beam serviced by the gateway. A transmit power factor and an interference factor are determined for each UT based on the respective return link signal. A total interference factor is determined for the UTs based on the transmit power factors and the interference factors. A residual capacity level for the satellite beam is determined based on the total interference factor and a noise power factor. The gateway receives an admission request from a further UT requesting admission for transmission of a return link signal. The gateway determines whether to grant the admission request based on a required capacity level for the return link signal of the further UT relative to the residual capacity level.