PurposeHealth systems are progressively stressed by health spending, which is partially explained by the increase in the cost of health technologies. Countries have defined processes to prioritize interventions to be covered. This study aims to compare for the first time health technology assessment (HTA) processes in Canada and Chile, to explain the factors driving these decisions.Design/methodology/approachThis is a health policy analysis comparing HTA processes in Canada and Chile. An analysis of publicly available documents in Canada (for CADTH) and Chile (for the Ministry of Health (MoH)) was carried out. A recognized political science framework (the 3-I framework) was used to explain the similarities and differences in both countries. The comparison of processes was disaggregated into eligibility and evaluation processes.FindingsCADTH has different programmes for different types of drugs (with two separate expert committees), whereas the MoH has a unified process. Although CADTH’s recommendations have a federal scope, the final coverage is a provincial decision. In Chile, the recommendation has a national scope. In both cases, past recommendations influence the scope of the evaluation. Pharmaceutical companies and patient associations are important interest groups in both countries. Whereas manufacturers and tumour groups are able to submit applications to CADTH, the Chilean MoH prioritizes applications submitted by patient associations.Originality/valueInstitutions, interests and ideas play important roles in driving HTA decisions in Canada and Chile, which is demonstrated in this novel analysis. This paper provides a unique comparison to highly relevant policy processes in HTA, which is often a research area dominated by effectiveness and cost-effectiveness studies.