The poor surface shear resistance of Ti6Al4V alloy limits its applications involving moving components. To improve its tribological properties, a duplex treatment method involving plasma nitriding and MoS₂ coating was proposed. The objective was to enhance load-bearing capacity, optimize surface roughness, and extend the lifetime of the MoS₂ coating. Plasma nitriding significantly increased surface hardness by 2.3 times compared to untreated alloy. MoS₂ coating on the hardened subsurface resulted in low friction coefficients of 0.05 at 25 % relative humidity. The duplex treated sample with a rough subsurface showed a lifetime of 11.90 h, six times better than the smooth subsurface sample. Higher subsurface roughness facilitated lubricant storage, release, and the formation of a continuous tribofilm, resulting in longer lifetime.