High cell operation temperature causes a significant reduction in cell efficiency. Besides, this high temperature reduces the cell lifespan and physical damages could happen due to thermal stresses. An advanced and efficient cooling scheme is obligatory to operate a high concentration solar module under its recommended operating conditions. The main objective of this work is to design and optimize a microchannel heat sink in terms of channel geometry for high concentration photovoltaic module works under high solar concentration for more efficient and uniform cooling. A complete three-dimensional model for the high concentrator photovoltaic module coupled with the microchannel heat sink is developed. A densely packed high concentration solar module consists of AZURSPACE product triple-junction solar cells (electrical efficiency is 43.2% at a cell temperature of 25 °C) is considered as a heat source in this work. The multi-objective optimization method is adopted to obtain the optimum channel dimensions. Both channel width and height are defined as variable parameters. The optimum design is obtained then its thermal performance is investigated under different working conditions. The results confirmed the ability of the optimized cooling device to offer efficient thermal management and uniform cooling for a densely packed high concentration solar module.