Background: The oral health of people with schizophrenia (PWS) is very poor, suggesting a need for oral health promotion programmes with a high level of evidence. The aim of the EBENE study (Clinicaltrials.gov: NCT02512367) was to develop and evaluate the effectiveness of a multidisciplinary therapeutic educational programme in oral health (TEPOH) for PWS. Methods: A multicentre cluster randomised controlled trial, with outpatient psychiatry centres as the unit of randomisation, was designed to compare the effectiveness of TEPOH (intervention group) versus standard care (control group). The trial was conducted in 26 outpatient psychiatry centres in France (14 in the intervention group, 12 in the control group). Eligible patients with a diagnosis of schizophrenia were enroled between 2016 and 2020 and followed for 6 months. The TEPOH group received a multicomponent intervention (comprising an introductory session, three educational sessions, and a debriefing session). The primary endpoint was the evaluation of periodontal disease as a community periodontal index (CPI) score ≥ 3 at Month 6. The trial was completed using a qualitative approach based on semi-structured interviews with caregivers conducted between July 2018 and December 2019. The trial was stopped early due to difficulties in recruiting patients. Results: Overall, 81 patients (of 250 planned) were included, and 54 patients completed the trial: 40 in the TEPOH group and 14 in the control group. At baseline, the percentage of CPI ≥ 3 was 42.5% in the TEPOH group and 9.1% in the control group. At Month 6, the percentage of CPI ≥ 3 was 20% in the TEPOH group and 14.3% in the control group. The qualitative evaluation underlined that the professionals emphasised the “seriousness” and “assiduity” of the patients’ participation in this programme and that the TEPOH reinforced carers’ investment in oral hygiene. It also highlighted structural factors (lack of resources for professionals, lack of teeth in PWS, COVID-19 pandemic) that may have exacerbated the difficulties with enrolment and follow-up. Conclusions: The effectiveness of this TEPOH, developed for PWS as part of the EBENE study, has not been demonstrated. Certain aspects of the programme’s content and implementation need to be reconsidered. In particular, an adapted subjective measurement scale should be developed.