Direct‐conversion radio frequency transceivers are well‐substantiated structures for today's wireless communication systems due to their ability in complexity reduction, cost, and power consumption. The unavoidable mismatch between the in‐phase (I) and quadrature‐phase (Q) branch of the analog front‐ends in the direct‐conversion transceiver leads to degrading the performance of communication systems. In this article, we address the estimation and compensation of the IQ imbalance (IQI) parameters for both the transmitter (TX) and receiver (RX) in multiple‐input/multiple‐output systems with space‐time block code (STBC) in the digital domain. This article proposes a pre‐combiner estimation and compensation of the channel and the frequency‐independent IQI scheme based on the repetitive transmission of the pilot sequence using the least square technique. It is worth noting that the proposed method can be extended to any orthogonal STBC. Moreover, the study is applied to IQI in other scenarios including only TX and only RX. Simulation results show that the proposed method achieves better performance in comparison with the existing post‐combiner technique. Furthermore, the proposed method requires lower computational complexity when the number of receive antennas is limited.