Critical exponents offer important information concerning the interaction mechanisms near the paramagnetic to ferromagnetic transition. In this work a Monte Carlo–Metropolis simulation of the critical behavior in La 2/3Ca 1/3MnO 3 thin films is addressed. Canonical ensemble averages for magnetization per site, magnetic susceptibility and specific heat of stoichiometric manganite within a three-dimensional classical Heisenberg model with nearest magnetic neighbor interactions are computed. The La 2/3Ca 1/3MnO 3 thin films were simulated addressing the thickness influence and thermal dependence. In the model, Mn magnetic ions are distributed on a simple cubic lattice according to the perovskite structure of this manganite. Ferromagnetic coupling for the bonds Mn 3+–Mn 3+( e g – e g ′), Mn 3+–Mn 4+( e g – d 3) and Mn 3+–Mn 4+( e g ′– d 3) were taken into account. On the basis of finite-size scaling theory, our best estimates of critical exponents, linked to the ferromagnetic to paramagnetic transition, for the correlation length, specific heat, magnetization and susceptibility are, respectively: v=0.56±0.01, α=0.16±0.03, β=0.34±0.04 γ and γ=1.17±0.05. These theoretical results are consistent with the Rushbrooke equalitiy α+2 β+ γ=2.