The purpose of this study is to investigate the effect of TiB2 content on the microstructure and wear behavior of nano-TiB2p/2024Al composites fabricated by laser direct energy deposition (L-DED). The dry sliding friction and wear behavior was evaluated using a ball-on-disk tribometer by sliding samples against a 6-mm diameter GCr15 (AISI52100) steel ball under applied loads of 2.2 N at room temperature. Microstructural characterization of the as-deposited 2024Al alloy showed the presence of oriented columnar grains. Once 3 wt% TiB2 particles were introduced, the as-deposited microstructure consisted of a mixture of columnar and equiaxed grains. It was found that the addition of TiB2 particles can significantly improve the wear resistance of L-DEDed 2024Al. For instance, the wear-rate of an 8 wt% TiB2p/2024Al matrix composite with full equiaxed grains is almost 20 times lower than that of the unreinforced alloy. A grain morphology-induced wear mechanism for the L-DEDed TiB2p/2024Al composites is proposed and is dominated by mutual oxidation and abrasive wear. The research results are beneficial to understand the wear mechanism of L-DEDed nano-TiB2p/2024Al matrix composites and can also provide theoretical guidance for the selection of TiB2 content.