<p>To meet the increasing demand for continuously enhancing engineering performance and energy efficiency in a variety of aerospace and energy applications, structural materials with high strength at ultra-high temperatures are urgently required. In the past decade, refractory multi-principal element alloys (RMPEAs), particularly those containing elements with high melting temperatures (<i>T</i>_m) such as W and Ta (hereafter denoted as WTa-RMPEAs), have garnered extensive interest due to their exceptional strengths and thermally stability at high temperatures. Characterized by high <i>T</i>_m, sluggish diffusion, and severe lattice distortion, WTa-RMPEAs exhibit chemical composition fluctuations at different scales, leading to unique mechanical properties and deformation behavior. In this paper, an initial summary is provided of the mechanical properties of typical WTa-RMPEAs at room and high temperatures and the differences in deformation behavior and underlying mechanisms between RMPEAs and conventional alloys are discussed. Additionally, strengthening and toughening strategies and the suggested deformation mechanisms were reviewed. Finally, the challenges in revealing the actual deformation mechanism of WTa-RMPEAs were described, and a brief perspective on the future research of the mechanical behavior of WTa-RMPEAs was proposed.</p>