Background: Insomnia is a prevalent disorder associated with substantial impairment. Homeopathy has been proposed as a complementary treatment for insomnia, but its clinical effects remain uncertain. This systematic review assessed the efficacy, effectiveness, and safety of homeopathic treatments for insomnia. Methods: Prospective comparative studies evaluating any homeopathic preparation for insomnia were included. Searches in MEDLINE, EMBASE, seven additional databases, and three trial registries were conducted through August 2025. Risk of bias, intervention complexity, model validity, and pragmatism were assessed using respectively RoB 2, ROBINS-I, iCAT, MVHT, and RITES. Data were synthesized using random-effects meta-analyses, and certainty of evidence was evaluated using GRADE. Results: Eight randomized controlled trials (RCTs; n = 364 participants) and four non-randomized studies on interventions (NRSIs; n = 517) met the inclusion criteria. In adults, sleep quality (MD = −2.6 points; 95% CI −5.5 to 2.6; low certainty) and insomnia severity (MD = −3.2; 95% CI −5.68 to −0.72, moderate certainty) were reported in one RCT each. For total sleep time, the pooled MD of three RCTs was 0.65 hours (95% CI −0.9 to 2.2; low certainty). In children, one open-label RCT suggested a difference in insomnia severity, but certainty of evidence was very low. Adverse events were rarely reported, resulting in low certainty evidence. Conclusions: The current evidence is mainly limited by imprecision and risk of bias. The available evidence does not allow firm conclusions regarding the effects of homeopathy for insomnia. High-quality, replicated trials with systematic adverse-event monitoring are needed. Registration: Prospero 2025 CRD420251015627