There is a growing emphasis on healthcare professionals' (HCPs) role in managing cardiometabolic risk factors to reduce health disparity for immigrants in developed countries. This scoping review aimed to analyse evidence about HCPs' knowledge, attitudes, and practices (KAP) of managing cardiometabolic risk factors among Southeast Asian (SEA) immigrants in developed countries. Primary studies from inception to July 17, 2023, from four databases: PubMed/Medline, Embase, PsycINFO, and CINAHL were included. This review followed the Joanna Briggs Institute (JBI) scoping review methodology and reported in line with PRISMA-ScR. Of 619 identified studies, seven met the inclusion criteria. All studies discussed HCPs' knowledge, six explored attitudes, and three described practices specific to SEA immigrants. The extracted data were analysed using descriptive qualitative content analysis and classified into barriers and facilitators. Barriers included cultural discordance and acculturation challenges (patient level); gaps in cultural understanding, communication and clinical skills (healthcare team level); limited immigrant-specific resources (organisation level); and funding constraints (environment level). Facilitators included community and provider support (patient level), awareness and desires to provide immigrant-specific care (healthcare team level), availability of culturally appropriate services (organisation level), and multicultural agendas and policies (environment level). The barriers and facilitators faced by HCPs caring for SEA immigrants with cardiometabolic syndromes share similarities with other immigrant groups. Future research focused on co-production involving immigrant patients, their communities, and HCPs in healthcare service design is required to support HCPs in providing culturally appropriate care and promoting health equity regardless of ethnic, cultural, or linguistic backgrounds.