Classical adaptive sidelobe canceller (CASLC) schemes which use only complex spatial weights are inherently narrowband, and consequently perform poorly when attempting to suppress wideband interference. This paper presents a novel solution to this problem by using tapped delay line filters in each spatial auxiliary channel, and utilizing the adaptive space-time processing for performing the required null. This sidelobe canceller is referred to as adaptive space—time sidelobe canceller "ASTSLC". The higher performance achieved by the ASTSLC architecture comes at the cost of a considerable increase in its complexity. ASTSLC technique can be used for compensation due to bandwidth degradations, channel mismatching, and multipath phenomena. In this work, the problem of bandwidth compensation is considered. The objective of our analysis is to develop some insight into the way in which space—time processing leads to performance improvement as compared to the CASLC. Moreover, some quantitative estimates of how the performance varies with array antenna (space processing) and transversal filter (time processing) parameters are also investigated and presented.