Phnom Penh retains a substantial stock of colonial-era shophouses, villas and modernist civic buildings, yet the skills required to conserve and adaptively reuse them are in short supply. This paper identifies vocational training gaps for the conservation and adaptive reuse of heritage buildings in Phnom Penh and proposes a response in the form of a competency framework and a short-course curriculum. The study adopted a qualitative design based on semi-structured interviews with 38 contractors, architects and heritage officials working on or regulating heritage projects in the city. Interview transcripts were analysed thematically, and competencies were mapped against existing vocational programmes offered by public training institutions and private providers. The findings reveal that the most acute gaps lie in lime-based mortar and render work, timber repair and consolidation, the diagnosis of moisture and structural deterioration, and the documentation practices required by heritage permitting. Contractors reported that skilled workers learn on site without any formal credential, architects reported difficulty in specifying traditional materials, and officials reported an inability to verify contractor competence during permit review. Drawing on these results, the paper proposes a three-tier competency framework covering craft, technical and supervisory levels and outlines a modular short-course curriculum of 120 hours that can be delivered through the national technical and vocational education and training system. The implications extend to other Southeast Asian cities where rapid redevelopment threatens historic fabric and where certification of conservation skills remains absent.