Aluminum is the most abundant metal in the earth’s crust and its toxicity potentially limits the growth of plants grown in acid soils. The phytotoxic effects of aluminum on the seed germination and initial growth of Schinus molle seedlings were investigated in the present study. The treatments consisted of six aluminum concentrations (0, 25, 50, 100, 150 and 200 mg L-1) in the form of chloride (AlCl3) with four replicates of 12 seeds each. The majority of the evaluated variables responded in a negative quadratic form to Al concentrations. Our results indicate that intermediate Al concentrations tested were more harmful than the highest in this experiment for most of the evaluated variables, which shows that S. molle seeds have the potential to overcome the harmful effects of Al and to germinate in environments with high concentrations of this metal.