The healthcare sector represents a major source of waste production, and healthcare workers (HCWs) are crucial in waste management. Educational interventions (EIs) can be delivered through a single component (mono-component) or by combining different components (multi-component); although they have a potential impact on the sustainability of healthcare, their effectiveness in waste management still needs to be identified. The aim of this systematic review and meta-analysis was to describe EIs to improve waste management knowledge, attitudes, and practices among HCWs and provide an estimate of their effectiveness. Six relevant databases were searched; 24 articles were included, and 19 were meta-analyzed. These were mainly from low-income countries and did not consider EIs for recycling, reducing, and reusing. Compared to the mono-component EIs, the multi-component Eis showed a higher statistically significant positive post-intervention effect on knowledge, with greater retention in the medium–long term, and on practices, particularly among non-hands-on HCWs. The effects of the EIs on attitudes were not significant. Our results suggest that multi-component EIs should be preferred to improve waste management standards in the healthcare sector. Given the heterogeneity found among EIs, the standardization of types, content, duration, and assessment methods should be considered. Finally, their harmonization at a global level could influence international and national policies on sustainability.