ABSTRACT This study assessed the cost-effectiveness of the 20-valent pneumococcal conjugate vaccine (PCV20) in Canadian infants aged <2 years versus the standard of care (SoC), a 13-valent pneumococcal conjugate vaccine (PCV13), or a potential 15-valent pneumococcal conjugate vaccine (PCV15). A decision-analytic Markov model was developed to compare PCV20 with PCV13 or PCV15 in a 2 + 1 schedule over 10 years. Vaccine effect estimates (direct and indirect) across all ages were informed by PCV13 clinical effectiveness and impact studies as well as PCV7 efficacy studies. Epidemiologic, clinical, health state utilities, utility decrements, cost per event, and list price data were from Canadian sources where available. Clinical and economic outcomes related to invasive pneumococcal disease (IPD), hospitalized and non-hospitalized pneumonia, and simple and complex otitis media (OM) were calculated for each strategy. Cost-effectiveness was evaluated from the publicly funded healthcare system perspective. Over 10 years, PCV20 versus PCV13 was estimated to avert over 11,000 IPD cases, 316,000 hospitalized and non-hospitalized pneumonia cases, 335,000 simple and complex OM cases, and 15,000 deaths, resulting in cost savings of over 3.2 billion Canadian dollars (CAD) and 47,000 more quality-adjusted life years (i.e. dominant strategy). Compared with PCV15, PCV20 was estimated to result in over 1.4 billion CAD in cost savings and 21,000 more QALYs (i.e. dominant strategy). PCV20 was dominant over both PCV13 and PCV15. Given broader serotype coverage, substantial incremental benefits and cost-savings, PCV20 should be considered as a replacement for the SoC in the publicly funded Canadian infant immunization program.