This research intended to assess the influence of income levels on micro and small business operators’ participation in social security fund (SSF) in Moshi Municipality, Tanzania. This study was guided by the Social Protection Theory (SPT) which described that Social Security Funds provides benefits to both individuals and households to propagate losses of earnings caused by sickness, maternity, employment injury, invalidity, old age or death. This research used a concurrent research design with a mixed research approach. The target population for the study was business operators found in Moshi Municipality totaling to 6,884. A sample size of 378 respondents obtained from Yamane (1964) formula through stratified random sampling and purposive Sampling. A structured questionnaire was administered as the tool for collecting primary data and Key informant Interviews were administered to gather additional qualitative data. Validity was ensured through discussion of the instrument with experts. Reliability of the instruments was obtained having Cronbach’s Alpha coefficient of 0.76. Ethical considerations were adhered toward conducting this study. Descriptive statistics and content analysis was used for quantitative and qualitative data respectively. The study revealed that level of income affects the way that small or micro business operator perceives the value of social security funds in Moshi Municipality. This study recommends that social security funds should set a minimum income threshold for participation to ensure that micro and small business operators with low level of income participate in the social security funds in Moshi Municipal Council.