BACKGROUND: Functional motor disorder often causes persistent disabling symptoms that are associated with high healthcare costs. In recent years, specialist physiotherapy, informed by an understanding of functional motor disorder, has emerged as a promising treatment, but there is an absence of evidence of its effectiveness from large randomised controlled trials. METHODS: We conducted a pragmatic, multicentre, randomised controlled trial, comparing specialist physiotherapy for functional motor disorder to treatment as usual, which was defined as community neurological physiotherapy. The primary outcome was the Short Form questionnaire-36 items Physical Functioning domain at 12 months (scale range 0-100, with 100 indicating optimum health). The trial was powered to detect a 9-point difference in the primary outcome with 90% power at the 5% level of significance. Secondary domains of measurement included a patient perception of improvement, health-related quality of life, mobility, anxiety, depression and illness perception. We also completed a health economic analysis with the primary aim of calculating the mean incremental cost per quality-adjusted life-year over 12 months. In prespecified analysis plans, we excluded participants from the primary analysis if they were unable to receive their trial-allocated treatment due to COVID-19 lockdown restrictions. Sensitivity analysis explored the impact of this decision. RESULTS: Between 19 October 2018 and 31 January 2022, 355 adults with functional motor disorder were randomised (1 : 1) to specialist physiotherapy ( = 179) and treatment as usual ( = 176). Eighty-nine participants were excluded due to COVID-19 disruptions. Retention for the primary analysis was 90% for both groups, leaving 241 participants in the primary analysis. At 12 months, there was no between-group difference in the primary outcome (adjusted mean difference 3.5, 95% confidence interval -2.3 to 9.3). However, several secondary outcomes favoured specialist physiotherapy, including the participant perception of improvement, Short Form questionnaire-36 items Mental Health domain, confidence in the diagnosis and two subscales (Personal Control and Illness Coherence) of the Revised Illness Perception Questionnaire. There were no differences in the remaining outcomes. At 6 months, the following outcome measures were significantly different, in favour of specialist physiotherapy: participant perception of improvement, the Short Form questionnaire-36 items Physical Role Limitations, Short Form questionnaire-36 items Social Functioning, Short Form questionnaire-36 items Mental Health, EuroQol-5 Dimensions five-level version utility score, confidence in the diagnosis and three subscales (Timeline Cyclical, Personal Control and Treatment Control) of the Revised Illness Perception Questionnaire. No outcomes significantly favoured treatment as usual. In the health economic analysis, the incremental cost per quality-adjusted life-year gained from a health and social care cost perspective was £4133 with an 86% probability that specialist physiotherapy is cost-effective compared to treatment as usual at a cost-effectiveness threshold of £20,000 per quality-adjusted life-year gained. There were no adverse events related to physiotherapy. CONCLUSION: Specialist physiotherapy was not superior to treatment as usual for the primary outcome, the Short Form questionnaire-36 items Physical Functioning domain at 12 months. However, a number of secondary outcome measures favoured specialist physiotherapy at 6 and 12 months. There is a high probability that specialist physiotherapy is cost-effective. LIMITATIONS: Participants in treatment as usual waited longer to start physiotherapy, which resulted in a shorter time between concluding treatment and completing the primary outcome. Most outcome measures, including the primary outcome, were participant reported, which may have been biased by perceptions of the randomised treatment allocation. FUTURE WORK: Future work should identify or develop more suitable outcome measures for functional motor disorder research, explore who is most likely to benefit from specialist physiotherapy and identify alternative interventions for those unlikely to benefit from this treatment. Additional work is needed to adapt treatment to meet the needs of minority groups and young people. FUNDING: This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number 16/31/63.