The majority of adults in the United States fail to meet the Centers for Disease Control and Prevention (CDC) physical activity (PA) guideline recommendations for health promotion. Despite evidence of disparities by sexual orientation in adverse health outcomes related to PA, little is known about whether PA patterns and the likelihood of meeting these guidelines differ between heterosexual and sexual minority (SM) men and women. In 2018, we pooled unweighted respondent data from Kaiser Permanente Northern California Member Health Surveys conducted in 2008, 2011, and 2014/15 (N=42,534) to compare PA patterns among heterosexual and SM men and women. In total, 38.8% of heterosexual men, 43.4% of SM men, 32.9% of heterosexual women, and 40.0% of SM women meet the CDC PA guidelines, yet there was no statistically significant difference in the adjusted odds of meeting these guidelines. Compared with heterosexual women, SM women engage in PA more frequently [odds ratio=0.81; 95% confidence interval (CI), 0.74-0.89], for more minutes per week on average (12.71; 95% CI, 4.85-20.57), and at higher levels of intensity (relative risk ratio=1.26; 95% CI, 1.02-1.56). Compared with heterosexual men, SM men engage in PA more frequently (OR=0.85; 95% CI, 0.74-0.98), for fewer minutes per week on average (-12.89; 95% CI, -25.84 to 0.06), and at lower levels of intensity (relative risk ratio=0.83; 95% CI, 0.67-0.99). We find that SMs get more frequent PA than their heterosexual peers, which suggests that the higher prevalence of obesity and other PA-related adverse health outcomes among SMs may be due to factors other than PA patterns.