The behaviour of women in providing, obtaining, and utilizing food can determine the status of household food security. Consumption of diverse food including animal protein is very important to prevent stunting. The level of energy consumption which is still below the national standard and the low consumption of animal protein by the people of West Nusa Tenggara Province contribute to the high number of stunting cases in West Nusa Tenggara Province, especially West Lombok Regency. To reduce it, the Government of West Lombok has provided guidance to coastal communities through extension activities on optimizing the marketing and processing of fish caught to fisherwomen. This study aims to find out about the role of extension workers in supporting household food security, analyse the influence of the role of extension workers on the behaviour of women fishermen and analyse the effect of women’s behaviour on the status of household food security. The research was conducted in Batu Layar District, in Meninting Village and Senteluk Village and Lembar District, Sheet Village and South Sheet Village. The research was conducted using an explanatory survey method with data collection through interviews with 60 respondents, observations, and in-depth interviews with several fisherwomen informants and key informant. Then the data was analysed by regression analysis. The results of the analysis indicate that the higher the role of the extension worker will be able to change the behaviour of fisherwomen, and changes in the behaviour of fisherwomen will improve the status of household food security. Thus, increasing the competence of extension workers must be comprehensive, not only focusing on the production aspect but also on the importance of food and nutrition aspects. Then, it is necessary to encourage an increase in the role of extension workers in conducting counselling and mentoring to change the behaviour of fisherwomen in processing, selecting, providing, and distributing diverse and nutritious food to each household member.