Voice behavior is important for innovation, mistake prevention and organizational performance. Because organizational trust increases employees' possibility of disclosing their real inner ideas, we examined the relationships between organizational trust and voice behavior, focusing especially on the avenue of impelling people to feel a higher level of authenticity. We used multiple methods to analyze the relationship. First, we used two separate surveys (Studies 1a and 1b) with different questionnaires and populations to analyze the mediation relationship and generalize the results. Then, to test the causal path, an experiment (Study 2a) in which organizational trust was manipulated was designed. The results showed that employees' authenticity mediated the relation between organizational trust and voice behavior. To further test the causal effect of authenticity in the above mediation, authenticity was manipulated in another experiment (Study 2b). The results illustrated that higher levels of authenticity directly led to higher levels of voice behavior. These results support the hypothesis and expound on the psychological mechanism of how organizational trust increases voice behavior. The theoretical and practical implications of these findings are discussed.