In this paper, we attempted to modify the self‐made two‐dimensional MoS2 nanosheets by oleic diethanolamide (OD) with a simple one‐step route to obtain OD‐MoS2. The OD‐MoS2 nanosheets were confirmed by a series of characterizations. The results showed that the MoS2 nanosheets could be chemically covered with OD molecules to form CS bond, so as to distinctly improve the dispersibility and stability of OD‐MoS2 nanosheets in base oil. Furthermore, the tribological properties of OD‐MoS2 nanosheets in base oil were comprehensively studied by four‐ball tester. In detail, the average friction coefficient and average wear scar diameter of 0.08 wt.% OD‐MoS2‐based oil were decreased by about 36.8% and 15.4% as compared with base oil, respectively, while its extreme pressure performance also was increased by about 15.2%. The results showed that OD‐MoS2 nanosheets exhibited the better tribological properties in oil because of the solved dispersibility.