To address the less-aggressive hit-to-kill interception problem for a high-speed maneuvering target, a predefined-time disturbance observer based switching guidance law is introduced. Firstly, the guidance problem is formulated in three-dimensional space. Secondly, a predefined-time disturbance observer is introduced as a means to accurately estimate the target’s maneuvering accelerations in line-of-sight frame. Thirdly, a novel switching guidance law is presented, allowing for the predetermination of the convergence time for the line-of-sight angular rates. Moreover, the proposed disturbance observer converges within the predefined time frame, it enables precise compensation for the target’s maneuvering accelerations. Both Lyapunov analysis and numeral simulation agree that the proposed guidance law achieves high interception accuracy and robustness.