The interlayer exchange coupling (Jex) in a perpendicularly magnetized synthetic antiferromagnet (p-SAF) is an important factor in the properties of domain wall (DW) motion driven by spin–orbit torque (SOT). In this study, we investigate experimentally and numerically how Jex affects the critical current density (Jc) of DW motion in an SOT-driven p-SAF. We also study how Jex affects the DW deflection angle (θDW), which is defined as the relative angle between the initial magnetization direction in the DW and the final one upon the injection of spin current. Positive correlation is found between Jex and Jc, which can be attributed to the suppression of θDW. Our results reveal how Jex affects the driving current of DW motion in an SOT-driven p-SAF.