This paper aims at identifying the elements of and impacting factors on succession planning at the academic and public libraries in the Mekong Delta, Vietnam. The research underpinned by transformational leadership theory used data from online survey of 172 participants from all thirteen public libraries and four selected academic libraries in the region. Twenty-three in-depth interviews of library leaders and managers of those libraries are conducted to get further information about emerging themes from the survey. Required elements of succession planning are indicated as an adequate talent pool, staff involvement, job descriptions, work performance assessments, and selection criteria. In the context of a country with only one leading Party such as Vietnam, the key impacting role is the Communist Party Committee. Other impacting factor on determining quality of successors is training programs. Impacting factors on leading and conducting succession planning are library leaders, general staff, and parent organization leaders. Furthermore, research also finds out some interesting correlations among variables of succession planning that contribute to the knowledge of library succession. This research provides potential successors with an awareness of challenges they may encounter to be promoted. This study also specifies evidence that candidates cannot automatically proceed to managerial positions without continuing efforts and self-improvement. Furthermore, the finding of the research contributes an assistance for library leaders in the process of selecting qualified staff for future managerial positions. Library leaders should consider these impacting factors because they affect the quality of successors and succession planning process. In addition, library leaders should pay attention to the correlations among age, qualification, position, and years of experience of employees with awareness of the existence of succession planning, the important role of succession planning, potential candidates, and promotion. These correlations should be considered because they also affect the quality of successors. The finding that general staff involvement helps to prevent library leaders from bias and demonstrate democracy and openness in succession planning is a new contribution to the literature. In addition, correlations among variables of succession planning are interesting and significant findings of the research. These correlations contribute to an understanding of factors in succession planning which has not been discussed in the literature so far.