The surface topography of a laboratory-grown MoS2 following radio frequency (RF) oxygen plasma treatment was studied using atomic force microscopy (AFM). At relatively low power levels, the etched material surface breaks into nano-scale linear troughs extending in two surface directions. In contrast, higher power plasma creates nano-scale hillocks and etched pits. The basal-plane-contraction effect resulting from the substitution of sulphur by oxygen during etching and the sputtering and redeposition of surface materials by bombardment by energetic particles present in plasma are believed to be responsible for thr surface topography formed in different ranges of plasma power.