Background: The ubiquitous use of social media by physicians poses professionalism challenges. Regulatory bodies have disseminated guidelines related to physicians' use of social media. Objective: This study had 2 objectives: (1) to understand what pediatric residents view as appropriate social media postings, and (2) to recognize the degree to which these residents are exposed to postings that violate social media professionalism guidelines. Methods: We distributed an electronic survey to pediatric residents across the United States. The survey consisted of 5 postings from a hypothetical resident's personal Facebook page. The vignettes highlighted common scenarios that challenge published social media professionalism guidelines. We asked 2 questions for each vignette regarding (1) the resident's opinion of the posting's appropriateness, and (2) their frequency of viewing similar posts. We also elicited demographic data (age, sex, postgraduate year level), frequency of Facebook use, awareness of their institutional policies, and prior social media training. Results: Of 1628 respondents, 1498 (92.01%) of the pediatric residents acknowledged having a Facebook account, of whom 888/1628 (54.55%) reported daily use and 346/1628 (21.25%) reported using Facebook a few times a week. Residents frequently viewed posts that violated professionalism standards, including use of derogatory remarks about patients (1756/3256, 53.93%) and, much less frequently, about attending physicians (114/1628, 7.00%). The majority of the residents properly identified these postings as inappropriate. Residents had frequently viewed a post similar to one showing physicians drinking alcoholic beverages while in professional attire or scrubs and were neutral on this post's appropriateness. Residents also reported a lack of knowledge about institutional policies on social media (651/1628, or 40.00%, were unaware of a policy; 204/1628, or 12.53%, said that no policy existed). A total of 372/1628 respondents (22.85%) stated that they had never received any structured training on social media professionalism. Conclusions: Today's residents, like others of their generation, use social media sites to converse with peers without considering the implications for the profession. The frequent use of social media by learners needs to change the emphasis educators and regulatory bodies place on social media guidelines and teaching professionalism in the digital age.