Both masturbation frequency and pornography use during masturbation have been hypothesized to interfere with sexual response during partnered sex as well as overall relationship satisfaction. However, results from prior studies have been inconsistent and frequently based on case studies, clinical reports, and simple binary analyses. The current study investigated the relationships among masturbation frequency, pornography use, and erectile functioning and dysfunction in 3586 men (mean age = 40.8 yrs, SE = 0.22) within a multivariate context that assessed sexual dysfunctions using standardized instruments and that included other covariates known to affect erectile functioning. Results indicated that frequency of pornography use was unrelated to either erectile functioning or erectile dysfunction (ED) severity in samples that included ED men with and without various sexual comorbidities or in a subset of men 30 years or younger (p = 0.28-0.79). Masturbation frequency was also only weakly and inconsistently related to erectile functioning or ED severity in the multivariate analyses (p = 0.11-0.39). In contrast, variables long known to affect erectile response emerged as the most consistent and salient predictors of erectile functioning and/or ED severity, including age (p < 0.001), having anxiety/depression (p < 0.001 except for a subset of men ≤ 30 years), having a chronic medical condition known to affect erectile functioning (p < 0.001 except for a subset of men ≤ 30 years), low sexual interest (p < 0.001), and low relationship satisfaction (p ≤ 0.04). Regarding sexual and relationship satisfaction, poorer erectile functioning (p < 0.001), lower sexual interest (p < 0.001), anxiety/depression (p < 0.001), and higher frequency of masturbation (p < 0.001) were associated with lower sexual and lower overall relationship satisfaction. In contrast, frequency of pornography use did not predict either sexual or relationship satisfaction (p ≥ 0.748). Findings of this study reiterate the relevance of long-known risk factors for understanding diminished erectile functioning while concomitantly indicating that masturbation frequency and pornography use show weak or no association with erectile functioning, ED severity, and relationship satisfaction. At the same time, although verification is needed, we do not dismiss the idea that heavy reliance on pornography use coupled with a high frequency of masturbation may represent a risk factor for diminished sexual performance during partnered sex and/or relationship satisfaction in subsets of particularly vulnerable men (e.g., younger, less experienced).