Community violence exposure (CVE) is associated with aggression among youth, particularly those who reside in low-income, urban neighborhoods. However, not all youth who experience CVE exhibit aggression. Working memory (WM) difficulties may interfere with attributions or retrieval of nonaggressive responses, suggesting that individual differences in WM may contribute to proactive and/or reactive aggression among youth who experience CVE. Participants were 104 low-income, urban youth (M = 9.92 ± 1.22 years old; 50.5% male; 95% African American). Youth reported on frequency of direct victimization and witnessing of violence in the community and completed two WM tasks. Teachers reported on youth proactive and reactive aggression. WM moderated the relation between direct victimization and proactive and reactive aggression, and between witnessing violence and reactive aggression. Among youth reporting less frequent victimization and witnessing, lower WM was associated with higher levels of proactive and reactive aggression. Among youth reporting more frequent direct victimization, lower WM was associated with higher levels of proactive aggression. Proactive and reactive aggression levels were similar among youth reporting more frequent witnessing regardless of WM levels. WM represents a potential target for early identification and intervention efforts to reduce reactive and proactive aggression among low-income, urban youth who are at elevated risk for CVE.