Technology is becoming more and more popular in public services in general and social insurance in particular in Vietnam. Although the social insurance software has been used since November 2020, the number of users is still limited so far. Therefore, this study aims at investigating determinants of the intention to use social insurance management applications of Vietnamese people. Applying a combination of three models (TAM, TRA and TPB), the study identifies five determinants of technology acceptance of users in their intention to use this application in Vietnam's Social Insurance, including Perceived usefulness, Perceived ease of use, Subjective norm, Perceived behavioral control, and Attitude towards usage. Data for the study were collected through a survey in three big Vietnamese cities: Ho Chi Minh City, Hanoi and Da Nang. Research results show that users' technology acceptance intention in social insurance in Vietnam is positively influenced by all five factors. From the analysis results, the study proposes recommendations related to improving the performance of the application, propagandizing the high applicability of VssID to the public. Policies and guidelines for the government to promote user's habit of using the application are also recommended.