Anti-lock braking system (ABS) is the most common safety system in the vehicles, which worksrnto increase the generated braking force between the tire and the road surface for enhancingrnpassenger safety specifically related to accident avoidance. However, designing an ABS is arnchallenging task considering the fact that it is highly nonlinear and a time varying system. Therninteraction between the tires and the road surface, the dynamics of the whole vehicle and therncharacteristics of key components in ABS are all nonlinear and time varying. Due to the nonlinearitiesrnof the brake actuation system, robust braking control system with a faster responsernis required to handle even sudden, extreme variations in driving conditions with little loss ofrntraction and steering ability.rnIn this thesis, out of the robust controlling mechanisms, a sliding mode controller based antilockrnbraking systemof a vehicle is introduced. The objective of this SMC based ABS is to keeprnthe wheel slip at an ideal value so that the tire can still generate lateral and steering forces asrnwell as shorter stopping distances in order to prevent the controlledwheel frombecoming fullyrnlocked. In order to control the system based on wheel slip, a Quarter car in terms of wheel sliprnis modelled and the model is validated by using open loop response analysis by usingMATLAB.rnThen a controller is designed and implemented using MATLAB. During our controller design,rnin order to resolve the drawback of SMC i.e. chattering, a nonlinear integral surface is defined.rnThe designed SMC based ABS and the conventional ABS are then evaluated under dry nominal,rndry concrete and dry slippery road types. And also the performance of the two systemsrnare evaluated under three different initial vehicle velocities and the system responses are thenrncompared in terms of wheel speed and stopping distance.rnAs the numerical simulation shows, on a dry nominal road, for an initial vehicle speed of 40rnkm/hr, the stopping distance that is obtained from the SMC based ABS and the conventionalrnABS are 14.5000mand 15.7080mrespectively. In the same road type, for an initial velocity of 90rnkm/hr, the stopping distance that is obtained from the SMC based ABS and the conventionalrnABS are 73.5122mand 79.6029m respectively. And also for an initial vehicle speeds of 40km/hrrnand 90km/hr, the braking time of the SMC based ABS is 0.11 Second and 0.39 Second fasterrnthan the conventional ABS respectively. At last, the proposed SMC based ABS achieves a robustrnsystem, minimum braking time and minimum stopping distance than the conventionalrnABS for all road types.rnKeywords: SlidingMode Control, Antilock Braking System, Sliding surface, wheel slip