The purpose of this study was to identify potential causes of violence and crime in informal settlements and residents’ strategies for response and prevention to these issues, as perceived by women living in Mathare informal settlement in Nairobi, Kenya. A total of 55 in-depth interviews were conducted with women living in the informal settlement in 2015-2016. A modified grounded theory approach was used to guide data collection and analysis. The most common contributor to violence and crime identified by women in Mathare informal settlement was idle youth, but leadership and government challenges, corruption and/or inadequacy of police, community barriers, tribalism, and lack of protective infrastructure also emerged as contributing factors. Despite facing many economic, environmental, and day-to-day challenges, women in Mathare identified violence and crime as predominant issues; thus, developing effective response and prevention strategies to these issues in informal settlements is paramount. Women suggest there are many strategies and initiatives to reduce and prevent violence and crime in informal settlements, but also identified barriers to implementing them. Findings suggest there is a need for trust-building between formal and informal organizations and institutions, systems of accountability, and long-term investment to foster sustainable and effective violence and crime response and interventions in these settlements.