Library succession planning has been addressed for more than two decades; however, the concept has only recently been developed in Vietnam. Succession planning provides numerous challenges for library leaders in Vietnam, including a small talent pool of successors; a lack of staff motivation; and an embryonic recruitment culture. This research helps to raise awareness of library leaders and library staff of the role of succession planning. Research was conducted through a multi-method approach at thirteen public and four academic libraries in the Mekong Delta, Vietnam. Data on succession planning challenges was collected through an online survey and interviews. This study utilized transformational leadership theory to investigate the challenges of library succession planning reported by library members. The findings related to challenges of library succession planning and possible solutions will assist library leaders in conducting the succession planning process.