In the present study, the wear behavior of as-plated and plasma-nitrided Ni-B-CNT coatings was taken into investigation. Ni-B-CNT composite was deposited on AISI 4140 steel using different concentration of CNTs ranging from 0.2 to 1 g.L-1, in an electroless bath. After the plating process, all samples were plasma nitrided in an atmosphere comprising of 25%N-2-75% H-2, at 400 degrees C, for 4 h. The friction and wear behavior of the composite coatings were evaluated using a pin on disk method at an applied load of 10 N. The samples were then characterized by means of XRD, FESEM, microhardness and surface roughness measurements. Worn surfaces were further analyzed by FESEM and EDS spectroscopy. Microhardness results revealed that the maximum hardness of 1550 HV was obtained for Ni-B 0.6 g.L-1 CNT plasma-nitrided sample. According to the results, increasing the CNTs concentration caused the as-plated Ni-B amorphous structure to change to semi-crystalline. Furthermore, the crevices formed during the hydrogen evolution reaction were observed to be filled up. Presence of CNTs not only decreased the grain size in the plasma-nitrided samples but also prevented excessive heat generation during the wear test, and thus the friction coefficient was declined during the test. Moreover, image of the worn surface of Ni-B 0.6 g.L-1 CNT plasma-nitrided sample indicated the smoothest wear trace with no apparent cracks and the highest wear resistance among all the samples was achieved. While, in Ni-B-1 g.L-1 CNT sample, agglomeration created asperities as well as large particles weakly bonded to the Ni matrix which ultimately led to an increase in the specific wear rate.