The paper investigates the effect of tungsten nanoparticles on the structure and mechanical properties of aluminum 5056 alloy. Using optical and scanning electron microscopy, the structure of the AA5056-W composite and the initial alloy is investigated. Introduction of 0.5 wt. % of tungsten nanoparticles does not modify the structure of the aluminum alloy, but due to dispersed hardening, it can increase the hardness and the values of the yield stress, ultimate tensile strength, and maximum deformations before fracture of the metal matrix. The Orowan mechanism prevails in increasing the machinical properties of aluminum 5056 alloy with dispersed hardening with tungsten nanoparticles. The destruction of materials is caused by the uneven distribution of tungsten nanoparticles in the aluminum matrix.