This study focuses on a topology-based design approach that can be applied to liquid-cooled heat sinks for high-heat-flux devices with the goal of improving heat dissipation and manufacturability. Specifically, the study investigates the use of additively manufactured topology-based lattice structures for the practicality and flexibility (of varying topology parameters) of complicated structures to achieve high heat transfer performance. The design restrictions were set such that the heat sink would occupy a 25 mm × 25 mm × 8 mm space and attach on a matching size heater. A gyroid lattice structure with high cell volume allowing high fluid flow rate was chosen to test its printability and its effects on heat transfer. Using computational iterative routines to modify lattice structures allowed changing parameters including gyroid cell size, y-mapping, thickness of fins, overall dimensions, and other parameters. Prototype of the heat sink design was made of aluminum alloy (AlSi10Mg) by additive manufacturing process (laser powder bed fusion). Experimental investigation involved testing additively manufactured heat sink on a ceramic (AlN) heater at varying heat loads and flow rates, and measuring corresponding heater temperature to calculate thermal resistance. Results suggest that although further design and validation efforts are needed to fully assess the capabilities, the topology-based, additively manufactured liquid-cooled heat sinks would potentially offer a promising alternative in terms of heat transfer and fluid flow characteristics, as well as manufacturability, and reduced weight, material usage, and production cost.