Background/Objectives: Erectile dysfunction (ED) affects up to 50% of men with type 2 diabetes mellitus (T2DM), yet the independent effects of oral antihyperglycemic medications on erectile function remain controversial. This study investigated associations between commonly prescribed antihyperglycemic medications and erectile function in Taiwanese men with T2DM. Methods: This cross-sectional study enrolled 242 Taiwanese men aged 18–80 years with T2DM. Erectile function was assessed using the International Index of Erectile Function–5 (IIEF-5). Participants were categorized by 12-month HbA1c patterns into well-controlled, variably controlled, and poorly controlled groups. Multiple linear regression models adjusted for demographics, metabolic parameters, and comorbidities examined medication–IIEF-5 associations. Results: The mean IIEF-5 score was 18.16 ± 5.68. None of the seven oral antihyperglycemic medication classes showed significant independent associations with IIEF-5 scores. However, glycemic control demonstrated a significant association with erectile function (F(2,192) = 3.390, p = 0.036), with well-controlled patients showing higher scores than poorly controlled patients (mean difference = 2.488, p = 0.032). Conclusions: In this cross-sectional study, better glycemic control was associated with improved erectile function in men with T2DM. No significant independent associations were observed between individual oral antihyperglycemic medication classes and erectile function after adjustment for glycemic control and other confounders. These findings suggest that glycemic management, rather than the independent effect of medication class, may be the primary determinant of erectile function in this population; however, causal inferences cannot be drawn from this cross-sectional design.