This work reports on the dimensionality effects on the magnetic behavior of Fe₃Ga₄ compounds by means of magnetic susceptibility, electrical resistivity and specific heat measurements. Our results show that reducing the Fe₃Ga₄ dimensionality, via nanowire shape, intriguingly modifies its electronic structure. In particular, the bulk system exhibits two transitions, a ferromagnetic (FM) transition temperature at T₁ = 50 K and an antiferromagnetic (AFM) one at T₂ = 390 K. On the other hand, nanowires shift these transition temperatures, towards higher and lower temperature for T₁ and T₂, respectively. Moreover, the dimensionality reduction seems to also modify the microscopic nature of the T₁ transition. Instead of a FM to AFM transition, as observed in the 3D system, a transition from FM to ferrimagnetic (FERRI) or to coexistence of FM and AFM phases is found for the nanowires. Our results allowed us to propose the magnetic field-temperature phase diagram for Fe₃Ga₄ in both bulk and nanostructured forms. The interesting microscopic tuning of the magnetic interactions induced by dimensionality in Fe₃Ga₄ opens a new route to optimize the use of such materials in nanostructured devices.