In Vietnam, consumers and buyers show strong concerns on safe vegetable quality. Yet, control of vegetable safety is difficult in a situation of small-scale farming. Concerning linking farmers to market, many studies emphasized the vital role of farmer organization, but few studies focus on the specific activities of quality control by collective action. This paper aims to describe the present patterns of collective action by vegetable farmers involved in the development of vegetable safety, with a special focus on quality control. It is based on case studies of nine vegetable organizations. The study concludes that group leadership and farmers' sense of responsibility are the main ways for current Vietnamese farmer organizations to ensure producing a high-quality product associated with long-term acquaintance as well as the same residence area of the farmers because they cherish their reputation.