Sexual difficulties (i.e., disturbances in normal sexual responding) have the potential to significantly and negatively affect men's social and psychological well-being. However, a review of published measurement tools indicates that most have limited applicability to gay men, and none offer a nuanced understanding of sexual difficulties, as experienced by members of this population. To address this omission, the Gay Male Sexual Difficulties Scale( GMSDS) was developed using a sequential mixed-methods approach. The 25-item GMSDS uses a 6-point frequency Likert-type response format and examines: difficulties with receptive and insertive anal intercourse (5 items each); erectile difficulties (4 items); foreskin difficulties (4 items); body embarrassment (4 items); and seminal fluid concerns (3 items). The measure's scale score dimensionality, assessed using both exploratory and confirmatory factor analyses, as well as scale score reliability and validity (e.g., known-groups and convergent) was tested and deemed to be satisfactory. Limitations of the current series of studies and directions for future research are discussed.