Not only antipsychotics but additional interventions such as education for people with schizophrenia are also needed to support optimal therapy. Studies with educational interventions have been conducted and show varied outcomes. The systematic review aimed to summarize and evaluate the effectiveness of studies regarding educational interventions for people with schizophrenia. Two electronic databases (PubMed and Science Direct) were used to find studies with criteria that were educational interventions for people with schizophrenia and focused on outcome measures related to improving knowledge, medication adherence, and other outcomes as an effect of educational interventions, randomized or randomized controlled trial studies, published between 2012 and 2022. The manual search of referenced articles was also applied. A literature search was conducted using the terms ("people with schizophrenia" OR "patients with schizophrenia") AND ("education" OR "knowledge") AND ("medication adherence" OR "medication compliance" OR "medication persistence"). Of the 666 studies, seven were eligible. Some educational interventions are part of a therapy program, while others are full psychoeducational programs that target not only the patient but also the patient's family. There was only one study that used counseling supported by leaflets delivered by a pharmacist. Another intervention used face-to-face interviews and discussions supplemented by modules or booklets, or giving booklets to patients and then following up by phone. Only one of the seven studies was effective in increasing patient knowledge. The rest did not measure knowledge but assessed other parameters, i.e., stigma and insight, symptoms, social functioning, relapse rate, or quality of life as the effect of educational intervention. Three studies showed a significant difference in improvement in medication adherence between the intervention and control groups; two studies were not significant, and the rest were unmeasured. It can be concluded that educational intervention had a positive effect on PwS and their families’ knowledge, improved medication adherence, and other outcomes as an effect of the educational intervention.