The aim of this research was to examine the relationships between gender, sociosexuality, the Dark Triad, romantic attachment, and experiences of mate poaching for short-term and long-term relationships. The research was conducted online with a sample of N=389 adult participants who were in a romantic relationship at least once. Anonymous Romantic Attraction Survey (ARAS) was used as a measure of mate poaching experiences, The revised Sociosexual Orientation Inventory (SOI-R) was used to measure sociosexual orientation, the Dark Triad Short Scale for the Dark Triad, and Experiences in Close Relationship Inventory for romantic attachment. The results showed that men are generally more inclined to mate poach for short-term relationships than women. Gender proved to be a significant predictor of mate poaching attempts for both shortterm and long-term relationships, but its significance was lost when other predictors were considered. Sociosexuality is shown to be predictive in explaining the variance of mate poaching attempts for both short-term and long-term relationships and being the target of poaching for shortterm relationships. Regarding specific Dark Triad traits psychopathy has the greatest positive contribution in explaining the variance of mate poaching experiences. Attachment anxiety significantly positively predicted the experience of being the target of mate poaching for shortterm relationships and poaching attempts for long-term relationships, while avoidance had a significant contribution only for long-term poaching attempts. Given that mate poaching is one of the evolved psychological adaptations with the function to increase reproductive success, studying the determinants of this behavior is important to better understand the dynamics of romantic relationships.