The family, as the most important social institution, plays a fundamental role in the health and stability of social relationships, while marital relationship quality is considered one of the factors contributing to family cohesion. In this regard, sexual awareness can play an important role in improving couples’ interactions, satisfaction, and intimacy. The present study aimed to examine the role of sexual awareness in marital relationship quality among married residents of Qazvin. This survey research involved married men and women residing in Qazvin, from whom 400 participants were selected using proportionate stratified random sampling. Data were collected through two researcher-developed questionnaires measuring sexual awareness and marital relationship quality and were analyzed using SPSS. Pearson’s correlation test revealed a positive and significant relationship between sexual awareness and marital relationship quality (r = 0/432, p < 0/01). Furthermore, all dimensions of sexual awareness, including sexual knowledge, attitudes, skills, sexual rights and responsibilities, and cultural and social awareness, were positively and significantly associated with the dimensions of marital relationship quality. The results of multiple regression analysis indicated that sexual skills, sexual knowledge, sexual attitudes, sexual rights and responsibilities, and cultural and social awareness, respectively, made the greatest contributions to explaining marital relationship quality, accounting collectively for 42/7% of its variance. Accordingly, enhancing sexual awareness and skills can contribute to improving couples’ interactions, increasing satisfaction and intimacy, and reducing marital conflicts. Therefore, developing targeted educational and counseling programs in this area is important for strengthening marital relationships and family foundations.