Individuals’ metaperceptions regarding how another person views them tend to be egocentrically biased by their own private self-knowledge: They overestimate the extent to which their traits, feelings, and intentions are ‘transparent’, perceiving more congruence between their inner self and the other person's impressions than actually exists. In the present article, we examine the factors, such as self-awareness and feelings of closeness, that increase individuals’ propensity to exaggerate their transparency to others. We also examine the interpersonal consequences of transparency overestimation and the related signal amplification bias, considering how they can reduce the likelihood of relationship formation, derail the seeking and provision of social support in ongoing relationships, and more generally lead to relational conflict. Lastly, we discuss the interventions available to reduce these biases.