Start-up organizations are informal and loosely structured, and they operate in a highly volatile environment that has a high attrition rate. This makes the employees of start-ups susceptible to stress, which may lead to turnover intentions. Industrial reports show that start-up organizations have a higher turnover ratio in comparison to that in other sectors. The purpose of this article is to explore the antecedents of job stress in Indian start-ups and to examine their relationship with job stress. Furthermore, the mediating role of job stress in the relationship between turnover intentions and the antecedents of job stress itself is also examined. Using snowball sampling, 1,000 employees of five start-up companies in India are targeted to record 473 responses. Post data cleaning, only 412 functional responses are used for the study. The analysis in the study is carried out using structural equation modelling. The results reveal that three role stressors and job insecurity positively influence job stress, which eventually leads to turnover intentions. The mediation analysis also reveals that job stress partially mediates the relationship between turnover intentions and job stressors that include job insecurity. The findings of this article will be useful for human resource (HR) managers in start-up organizations. The suggestions presented in this article will help HR managers to find ways to keep the employees free of stress, bringing down the rate of turnover intentions in the process. JEL Code: M