Commercial motorcycle operation (CMO) is a very huge business line in Nigeria and has become a source of livelihood to many Nigerians especially the youths. But the same system that came as succour to unemployed Nigerians became the source of worry in many cities in Nigeria, as the operators now use it as a means to perpetrate various crimes. This study examined the Public Perceptions of Patterns and Gender dimensions of Criminal activities by Commercial Motorcyclists in Nnewi South L.G.A., Anambra State, Nigeria. The theoretical thrust of the study is Routine activities theory. A mixed-method research design involving quantitative and qualitative approaches was utilised. The questionnaire schedule and in-depth interview guide were employed for data collection. A multistage sampling procedure was used in selecting a sample size of 350 respondents and a total of 8 participants for IDI schedules. Quantitative data were analyzed using descriptive statistics, while inferential statistics (Chi-Square) was employed to test stated hypotheses, while thematic analysis was used to analyse the qualitative data. Findings revealed that the patterns of criminal activities associated with CMO in Nnewi are swift snatching of valuables from victims, use of weapons to incite fear and incapacitate their victims and younger females are more susceptible to the above crimes, taking passengers to lonely spots to rob them with dangerous weapons, using motorcycles to spy on victims to provide information about the whereabouts of the victim to the major criminal group. The study, therefore, concluded that to avert this trend, it is important that individuals, communities, government, and all stakeholders in the society pull hands together to nip the phenomenon in the bud.