The search for employment opportunities in urban centers has led to the rise of the informal sector which comprises of street vendors with a large proportion being women. Women street vendors have formed or joined street vendors association to help them navigate street vending. This study was occasioned by the disparity gaps between allied associations supporting the rights of street vendors to operate in public spaces, the membership of street vendors into street vending associations and street vendors being incorporated in urban planning. The study assessed the effectiveness of street vendors associations among women street vendors in Nairobi City County basing on the following objectives; to examine factors influencing membership in street vendors associations, to assess the functions of street vendors associations, to evaluate the benefits and the challenges of street vendors associations. The study adopted descriptive survey design to collect qualitative and quantitative data using questionnaires, interviews and content analysis from published materials, journals, and magazines.