This study aimed to produce a list of the top 10 research priorities regarding physical activity, sedentary behavior, and sleep in pregnancy. Using the Delphi methodology, pregnant/postpartum individuals (N = 118), exercise professionals and healthcare providers (N = 55) listed up to 10 questions perceived as unanswered regarding physical activity, sedentary behavior, and sleep in pregnancy (Round 1). Respondents rated the proposed questions on a Likert importance scale (Round 2), and the sum of ratings received were totaled. Questions of priority regarding physical activity among pregnant/postpartum individuals (N = 67), healthcare providers and exercise professionals (N = 22) pertained to exercise prescription, impact of exercise on maternal and fetal outcomes and impact of exercise on pregnancy conditions, special population groups and clinical education and access to information. Sedentary behavior priorities included the impact of sedentary behavior on maternal and fetal outcomes, sedentary recommendations and exercise and sedentary positioning. Sleep research priorities included the impact of pregnancy on sleep, safety, sleeping aids and the effect of exercise on sleep. Pregnant/postpartum women, healthcare providers and exercise professionals prioritized questions that have in part been addressed by existing research, highlighting a need for improved knowledge translation from research to practice. They have also identified novel questions that warrant prioritization within future research.