The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has performed systematic  measurements of Φ meson production in the K⁺K⁻ decay channel at midrapidity in p + p, d+Au, Cu+Cu and Au+Au collisions at √s_NN =200 GeV. Results are presented on the Φ invariant yield and the nuclear modification factor R_AA for Au+Au and Cu+Cu, and R_dA for d+Au collisions, studied as a function of transverse momentum (1 < pT < 7 GeV/c) and centrality. In central and mid-central Au+Au collisions, the R_AA of  Φ exhibits a suppression relative to expectations from binary scaled p+p results. The amount of suppression is smaller than that of the π⁰ and the η in the intermediate pT range (2–5 GeV/c), whereas at higher _pT the Φ, π⁰ and η show similar  suppression. The baryon (protons and anti-protons) excess observed in central Au+Au collisions at intermediate _pT is not observed for the Φ meson despite the similar mass of the proton and the Φ. This suggests that the excess is linked to the number of constituent quarks rather than the hadron mass. The difference gradually disappears with decreasing centrality and for peripheral collisions the RAA values for both particles are consistent with binary scaling. Cu+Cu collisions show the same yield and suppression as Au+Au collisions for the same number of N_part. The R_dA of Φ shows no evidence for cold nuclear effects within uncertainties.