Objective: Vietnam, like many low/middle income countries, lacks the infrastructure to provide information and psychosocial support to cancer patients and their carers. We undertook a codesign process to develop a web resource to inform and support carers. Methods: Cancer carers and health care professionals' perspectives regarding information and support needs and the content and delivery of web-based supports, were explored via five focus groups (n = 39) and semistructured interviews (n = 4) in Vietnam in 2018. Focus groups and interviews were transcribed verbatim and analyzed using thematic analysis. Resource components were verified at two joint stakeholder workshops attended by 40 participants. Results: The development of a web-based resource was identified as an urgent need. A web-based resource was viewed as a suitable interface to provide support across regions in a sustainable way. The structure of the resource should include peer-led videoed advice, signposting to services and include official endorsement. The potential resource components identified includes (a) cancer causes and consequences; (b) hospital administration, treatment processes, and prices; (c) daily living; (d) emotional and supportive information; (e) skills training; and (f) nutrition and traditional medicine. Conclusion: The development of a web-based resource to deliver information and psychosocial supports to cancer carers and by-proxy patients is an urgent requirement in Vietnam. Next steps will include resource development and testing the resources ability to address the unmet needs of cancer carers and patients. A web-based resource to support cancer carers has the potential for application to other developing countries.