Background: Youth violence reduction is a public health priority, yet few studies have examined secular trends in violence among urban youth, who may be particularly vulnerable to numerous forms of violence. This study examines 10-year secular trends in the prevalence of violence-related behaviors among Philadelphia high school students. Methods: Repeated cross-sectional data were analyzed from 5 waves of the Philadelphia Youth Risk Behavior Survey (YRBS) from 2003 to 2013. Sex-specific multivariate regression models were used to examine secular trends in multiple types of violence, accounting for age, race/ethnicity, and sampling strategy. Results: In 2013, the most prevalent violent behavior was physical fighting among boys (38.4%) and girls (32.7%). Among girls, the prevalence of sexual assault and suicide attempts declined between 2003 and 2013 (ß = -0.13, p = 0.04 and ß = -0.14, p = 0.007, respectively). Among boys, significant declines in carrying a weapon (ß = -0.31, p < 0.001), carrying a gun (ß = -0.16, p = 0.01), and physical fighting (ß = -0.35, p = 0.001) were observed. Conclusions: Whereas the prevalence of some forms of violence stabilized or declined among Philadelphia youth during 2003-2013 time span, involvement in violence-related behaviors remains common among this population. Continued surveillance and evidence-based violence reduction strategies are needed to address violence among urban youth.