This paper investigates a fixed-time distributed voltage and reactive power compensation of islanded microgrids using sliding-mode and multi-agent consensus design. A distributed sliding-mode control protocol is proposed to ensure voltage regulation and reference tracking before the desired preset fixed-time despite the unknown disturbances. Accurate reactive power sharings among distributed generators are maintained. The secondary controller is synthesized without the knowledge of any parameter of the microgrid. It is implemented using a sparse one-way communication network modeled as a directed graph. A comparative simulation study is conducted to highlight the performance of the proposed control strategy in comparison with finite-time and asymptotic control systems with load power variations.