Findings from decades of research on romantic relationships have stressed the importance of romantic partners making accurate judgments of each other (e.g., Fletcher & Kerr, 2010, 2013). Research has demonstrated that there are two types of accuracy (West & Kenny, 2011). One form of accuracy (tracking accuracy) involves correctly detecting behavior patterns or traits when making judgments (e.g., Claire may know that John is intelligent), whereas the other form of accuracy (directional bias) involves overestimation or underestimation of these behavior patterns or traits when making judgments (e.g., Claire may think John is more intelligent than he actually is). One domain of relationships that has downstream effects on other relationship processes (e.g., satisfaction) is sexual communication. Miscommunication and misperceptions of sexual desires are common in romantic contexts (e.g. Muise, Stanton, Kim, & Impett, under review; Simms & Byers, 2009). However, the possible interplay between bias and accuracy in perceptions of partners' sexual advance behaviours and their capacity to influence romantic relationship outcomes has yet to be investigated systematically. The current study will address this gap in the literature, and also examine how adult attachment styles may moderate the effects of accuracy and bias on relationship outcomes. *Note that at the time of registration, data collection was in progress. However, no data had been looked at or analyzed.