Over 75% of children in Canada participate in organized sport (Active Healthy Kids Canada, 2015) and parents are an important source of support in youth sport participation (Omli & Wiese-Bjornstal, 2011). While many parents display good behavior on youth sport sidelines, some poor sideline behavior still exists and can detract from the positive environment desired for youth sport participants (Bowker et al., 2009). This study combined research from the fields of sport psychology and sport management to examine, from the perspective of parents, personal and situational factors that influenced parent behavior on youth sport sidelines. An ecological model (Bronfenbrenner, 1977) of influences on sport parent sideline behavior is presented and was used to create an online survey for ice hockey and baseball parents in provincial sport organizations in western Canada. In total 1040 parents completed the survey, 625 baseball parents and 415 hockey parents. Some differences based on personal (gender and sport experience) and situational (sport type, stakes, and occurrence) factors were found, but overall parents reported poor behavior was low and most poor behaviors were unacceptable, regardless of the situation. Results from this study can be used to educate parents and inform future sport parent sideline behavior studies.