This paper examines the connection between security sector reform and developmental outcomes, particularly how various forms of violence undermine development in fragile and conflict-affected states. Through literature reviews and case studies from Afghanistan, Solomon Islands, South Sudan, and Timor-Leste, it highlights the significant economic and social costs of violence, noting that globally the cost of violence containment is estimated at $9.46 trillion per year. The authors aim to provide insights to inform policy debates on security and development, stressing the need for robust responses to reduce different types of violence.