The impact of crime in the informal settlements in cities is enormous and extends beyond civilian causalities to the destruction of infrastructure and buildings. The fear of crime and violence continues to be pervasive in cities and is one of the top concerns in citizens' everyday lives. The main purpose of the study was to examine the influence of physical environment on crime in informal settlements of Kibra in Nairobi County, Kenya.The study concluded that planning solutions such as putting more eyes on the street, neighborhood cohesion through segregated planning approach and appropriate lighting can be effective tools to passive surveillance. The study recommends that planners should play a key role in improving the livelihood of people in informal settlements. Further, crime prevention through environmental planning should be implemented since it is not only an effective strategy to prevent crime but also cost effective and fits in the informal settlement. This study was found to be of importance in the on the field of urban studies particularly on crime in informal settlements.