Schizophrenia (SCZ) is a severe mental disorder characterized by complex pathological mechanisms and high treatment resistance, currently ranking among the diseases with the heaviest socioeconomic burden worldwide. Current antipsychotic medications are limited by factors such as insufficient response rates, limited cognitive improvement, and significant metabolic side effects. The ketogenic diet (KD), a metabolic intervention strategy characterized by high fat, very low carbohydrate, and moderate protein intake, has been shown to alleviate psychotic-like behaviors in both humans and animal models through multiple pathways, including modulating cerebral energy metabolism, reducing oxidative stress, and balancing neurotransmitter systems. Although current clinical trials on KD for SCZ have limited sample sizes, preliminary evidence indicates that it can alleviate psychiatric symptoms, cognitive dysfunction, and abnormal metabolic indicators in some patients, showing significant clinical translational value. This article systematically reviews the research progress on the association between KD and SCZ, discussing mechanisms of action, preclinical evidence, clinical exploration, and current challenges, while also suggesting future research directions. Key issues remain in the field, such as low patient adherence, poorly understood mechanisms of action, and a lack of individualized protocols. There is an urgent need for large-scale randomized controlled trials to provide high-level evidence supporting KD as an adjunctive therapy for SCZ.