Apparatus and method for ray tracing acceleration using a grid primitive. For example, one embodiment of an apparatus comprises: a grid primitive generator to generate a grid primitive comprising a plurality of adjacent interconnected primitives; a bitmask generator to generate a bitmask associated with the grid primitive, the bitmask comprising a plurality of bitmask values, each mask value associated with a primitive of the grid primitive; a ray tracing engine comprising traversal and intersection hardware logic to perform traversal and intersection operations in which rays are traversed through a hierarchical acceleration data structure and intersections between the rays and one or more of the adjacent interconnected primitives identified, wherein the ray tracing engine is to read the bitmask to determine a first set of primitives from the grid primitive on which to perform the traversal and intersection operations and a second set of primitives from the grid primitive on which the traversal and intersection operations will not be performed.