Cold spray is a feasible option to repair the versatile yet heat-sensitive Ti-6Al-4V (Ti64) alloy which has been widely used in aerospace, biomedical, marine and automotive industry. Nevertheless, the high yield strength of Ti64 makes it difficult to deform and attain dense coatings during cold spray deposition. While different process parameters have been investigated during cold spray deposition of Ti64 powders, the effect of powder size on the Ti64 deposits’ microstructure and wearability is not clear. Therefore, the influence of powder size on the cold-sprayed Ti64 deposit’s microstructure, residual stress, adhesion strength, coefficient of friction (CoF) and wearability have been investigated in this work. Three types of spherical Ti64 powders with median diameters (D50) of 23.1, 30.3 and 41.8 µm were deposited on Ti64 substrates using a common set of spray parameters. Their microstructure and wear performance were compared against those of Ti64 bulk coupon. The powders with the smallest D50 of 23.1 µm are found to result in the highest deposition efficiency (DE, 78.5%) and the lowest porosity (2.7%). Conversely, the powder with the largest D50 of 41.8 µm exhibits the lowest DE of 19.6%, highest porosity 14.6%, highest compressive residual stress and poorest adhesion to the substrate. With the understanding of the influence of powder size on deposits’ properties and wear performance, deliberate choices can be made regarding powder selection to achieve desired properties for specific cold spray applications.