Research on trust has burgeoned in the last two decades. Despite the growing interest in trust, little is known about the differences in trust between familiar and unfamiliar interactions. The current empirical study explored propensity to trust as predictors of trustworthiness over time in familiar and unfamiliar dyads. Utilizing latent growth modeling we found propensity to trust was related to initial perceptions of trustworthiness in unfamiliar pairs but not in familiar pairs. In addition, familiarity was related to initial perceptions of trustworthiness, but familiarity only influenced the change in integrity. However, there were significant differences in change variances between familiar and unfamiliar pairs. Implications of the findings are also discussed.