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Induction motors play an important role in many fields where variable frequency drive is required. Therefore, it is very important to properly control the speed of an induction motor. Three-phase induction motors, especially squirrel-cage induction motors, are nonlinear machines due to the interaction of time-varying electrical and mechanical parameters, unknown load inputs and motor conditions. Although field-oriented control provides reasonable control performance, its performance decreases due to the fact that it is a linear control method (because it uses proportional–integral–differential (PID) controllers) because it cannot handle parameter changes and nonlinear dynamics. The low disturbance rejection capability of conventional PI controllers requires the use of advanced controller structures. In this study, a field-oriented control of an induction motor with a fractional-order sliding mode controller (FOSMC) is proposed. This structure is used instead of PI controllers in the field-oriented control. The performance analysis of the field-oriented control structure developed using FOSMC has been carried out under five different scenarios such as constant speed, variable speed, sudden load change and variable motor internal resistance and reactance. The same scenarios are compared in detail with the conventional PI and sliding mode controller (SMC). In the studies conducted in the MATLAB/Simulink environment, the FOSMC controller emerged as the frontrunner, exhibiting the most accurate speed response profile under complex scenarios, followed by the SMC and PI control approaches, respectively.