Multiple-input multiple-output (MIMO) schemes have gained a lot of significance in the wireless communication ecosystems. Its usage in FSO communication scenarios is also of immense importance and could be utilized in the mixed RF/FSO cooperative relaying communication systems. The present chapter analyzes the performance of interference limited mixed RF/MIMO-FSO communication systems. By utilizing multiple apertures and receivers on the optical link, the communication system’s performance could be significantly enhanced. Although the cooperative relaying can improve the communication quality however, it is crucial to account for interference on the RF link. This system model is particularly relevant given the high-speed demands of the future wireless communication systems. This chapter explores a system where the RF link is extended using a high-speed optical wireless link. To increase the diversity on the FSO link, the Gamma-Gamma turbulence statistical model is employed. The RF link statistics for both intended and interfering signals are modeled using the Nakagami-m distribution, with an exact analysis presented for any value of the fading parameter m. This mathematical model provides an accurate framework for studying the impact of various parameters on the system performance.