This thesis examines the comprehension of the empty category and the third person lexical pronoun in object position in Brazilian Portuguese (BP). Experimental Results show that the processing of BP overt and nonovert objects is consistent with the leading idea underlying the Overt Pronoun Constraint (OPC) proposed by Montalbetti (84): in languages which allow a choice between an overt pornoun and an empty category, the overt pronoun specializes for the coreferential reading and the empty category for the bound reading.Experiment 1 compares the processing of overt pronouns and empty categories in object position in BP in structures in which these anaphors are A-bound by a subject and in structures in which they are A-bar bound by a topic. In experiment 2 , the difference between the coreferential vs. bound readings in BP is further investigated by comparing the possibility of the strict and sloppy readings for the overt pronoun and the gap in object position.