Objective. To examine the attitudes toward breastfeeding in public and perceptions toward appropriate durations. Methods. A total of 1036 adults completed an online survey on comfort levels toward themselves/partner or others breastfeeding in various locations, and perceived appropriate durations of breastfeeding from 3 months to over 2 years. We used multivariable ordered logistic regression to examine the association between demographic characteristics and comfort levels of one's breastfeeding and appropriate duration. Results. The sample was 68% female, 87% non-Hispanic white, 84% with college degree or higher, and 68% residing in the northeastern United States. After adjusting for demographic factors, men had significantly lower odds of being comfortable with having their partner (odds ratio [OR] range = 0.58-0.69, P < .05) or other women (OR range = 0.49-0.60, P < .05) breastfeed in malls, parks, restaurants, health clubs, and open spaces in general. Men had half the odds than women toward comfort with 2 or more years of breastfeeding (OR = 0.50, 95% confidence interval = 0.32-0.77). Ethnicity, residential setting, age, and education were not independently associated with comfort in breastfeeding in public or breastfeeding duration. Conclusions. In this mostly white, well-educated sample, women were significantly more comfortable with others and themselves/partner breastfeeding in public than males. The same was true regarding approval of longer durations of breastfeeding.