Crystalline Nb5Si3/Nb microlaminates were fabricated to a thickness of 20 μm by depositing the materials onto elevated temperature (750 °C) substrates. Modulation wavelengths of the microlaminates were varied (λ = 40 and 200 nm) while holding their silicide volume fraction constant to assess the effect of layer thickness on the composite properties. X-ray and selected area diffraction confirmed that both the metal and silicide layers exhibited a polycrystalline structure in the as-deposited microlaminates. Nanoindentation measurements of both microlaminates indicated that calculated elastic modulus values were similar to the values obtained by the rule-of-mixtures (ROM). Nanohardness values of the microlaminates increased with decreasing wavelength in a manner described by the Hall-Petch relationship. Vickers hardness (Hv) measurements were also found to be a function of the modulation wavelength, decreasing from 7.32 GPa at λ = 40 nm to 3.04 GPa at λ = 200 nm. Even with a Nb volume fraction of 50%, the λ = 40 nm microlaminate and the monolithic Nb5Si3 film exhibited similar Vickers hardness values of 7.5 GPa. These results show the significant role of modulation wavelength on the hardness, compressive strength, and toughness characteristics of a microlaminate composite.