Background and Objective: Healthcare workers (HCW) play an important role in vaccine acceptance of older adults (OA). A systematic review was conducted to identify effective educational interventions targeting HCW to improve advising on vaccinations. Methods: Medline, Scopus, Cochrane library and grey literature were searched for comparative studies on educational interventions targeting HCWs’ advising on vaccines for OA. No restrictions were applied to language and publication year. Where possible, a sub-analysis on publication year was conducted. In total 48 studies were included. The quality of the included studies was assessed with the RoB 2 for RCTs and the GRADE checklist for non-randomized studies. Study outcomes were categorized according to the Kirkpatrick model for effectiveness, consisting of four levels: reaction, learning, behaviour, and results (Kirkpatrick, 1996). Results: 17 Of the 27 RCTs and seven of the 21 non-randomized studies were at low to medium risk for bias, respectively. Most studies included reminder systems signalling patients due for vaccination. Other interventions were seminars, academic detailing and peer-comparison feedback. In the four articles reporting on the reaction-level, most HCWs were positive about the intervention. Moreover, two of five articles reporting on the learning-level, found positive changes in attitude or knowledge due to the intervention. Of fourteen studies reporting on the behaviour-level, those published after the year 2000 testing tailored reminders vs. usual care were most effective in increasing vaccination offering by HCWs. Of 34 studies reporting on the Results-level, those published prior to 2000 testing tailored reminders vs. usual care were most effective in increasing vaccination rates, followed by multicomponent interventions. Classic education only (e.g., lectures) was often ineffective, compared to other interventions. Conclusions: Tailored reminders are effective in supporting HCWs to suggest vaccines to OA, while classic education seems ineffective. Multicomponent interventions often combined classic educational methods with reminders and proved also effective.