A columbarium system and corresponding method of assembly is disclosed. The columbarium system includes niche cabinets, braces, brackets, face plates, and face plate security hardware. The niche cabinets are stackable in columns and rows to form a columbarium. The braces fit between front lip segments of adjacent niche cabinets. The brackets comprise bracket arms and face plate knobs. Bracket arms extend into braces, and face plate knobs support face plate corners. Face plates cover front sides of each niche cabinet. Face plates are supported and positioned by the face plate knobs, and face plates are secured in place by face plate security hardware. Shims may be inserted between adjacent niche cabinets to maintain spacing between the backs of niche cabinets.