When seeking to ensure financial sustainability of a health programme, existence of a line item in the Ministry of Health (MOH) budget is often seen as an essential, first step. We used immunization as a reference point for cross-country comparison of budgeting methods in Sub-Saharan African countries. Study objectives were to (1) verify the number and types of budget line items for immunization services, (2) compare budget execution with budgeted amounts and (3) compare values with annual immunization expenditures reported to WHO and UNICEF. MOH budgets for 2016 and/or 2017 were obtained from 33 countries. Despite repeated attempts, budgets could not be retrieved from five countries (Chad, Eritrea, Guinea Bissau, Somalia and South Sudan), and we were only able to gather budget execution from eight countries. The number of immunization line items ranged between 0 and 42, with a median of eight. Immunization donor funding was included in 10 budgets. Differences between budgeted amounts and expenditures reported to WHO and UNICEF were greater than 50% in 66% of countries. Immunization budgets per child in the birth cohort ranged from US$1.37 (Democratic Republic of Congo) to US$67.51 (Central African Republic), with an average of US$10.05. Out of the total Government health budget, immunization comprised between 0.04% (Madagascar) and 5.67% (Benin), with an average of 1.98% across the countries, when excluding on-budget donor funds. It was challenging to obtain MOH budgets in many countries and it was largely impossible to access budget execution reports, preventing us from assessing budget credibility. Large differences between budgets and expenditures reported to WHO and UNICEF are likely due to inconsistent interpretations of reporting requirements, diverse approaches to reporting donor funds, challenges in extracting the relevant information from public financial management systems and broader issues of public financial management capacity in MOH staff.