Attachment insecurity is negatively linked to sexual satisfaction in committed relationships, but we have much to learn about the specific mechanisms underlying this connection. With a sample of 1,421 participants from Amazon’s Mechanical Turk, we used structural equation modeling to explore whether sexual passion expression (harmonious, obsessive, inhibited) might mediate the association between insecure attachment (anxious and avoidant) and sexual satisfaction. Anxious attachment was linked to lower harmonious sexual passion, higher obsessive sexual passion, and higher inhibited sexual passion. Attachment avoidance was linked to lower harmonious sexual passion and higher inhibited sexual passion. Harmonious sexual passion was strongly linked to higher sexual satisfaction, and inhibited sexual passion was negatively linked to sexual satisfaction (for men). Sexual passion expression variables fully mediated the associations between attachment insecurity and sexual satisfaction. This study highlights that the expression of sexual passion may be important when considering the connection between attachment and sexual satisfaction.