This research evaluates the combination of nanosilica particles and ground limestone as mineral additions for white Portland cement (WPC) matrixes, envisioning architectural applications where the whiteness of the final product is a key feature. The WPC pastes and mortars were fabricated with additions of nanosilica and substitutions of cement by limestone. An experimental campaign was carried out to study the effect of the combination of nanoparticles and mineral additions over the hydration process, whiteness and mechanical performance of the WPC matrices. It was found that nanosilica in combination with limestone is an excellent option as a mineral addition for WPC, since it can improve its properties in the fresh and hardened states without altering the colour of the final product.