Increasing evidence supports the merits of speech therapy in Parkinson's disease, but the current practice of multiple in-house treatments is demanding for patients. We therefore assessed the effectiveness of remotely delivered and personalised speech therapy on improving quality of life and speech quality in persons with Parkinson's disease. We performed a single blinded randomised controlled trial (the PERSPECTIVE study), comparing 8 weeks of personalised remote speech therapy to no intervention (waiting list design). Patients with reduced speech intelligibility were included, regardless of disease stage or dysarthria severity. Patients were assigned randomly (1:1) to the intervention or control group. Measurements took place at baseline and after 8 weeks (both groups), and after 32 weeks (intervention group only). Patients were treated remotely by 20 experienced speech therapists. The primary outcome was disease-related quality of life at 8 weeks, assessed with the Parkinson's Disease Questionnaire 39 (PDQ-39). Data were analysed using analysis of covariance based on the intention-to-treat principle. This trial is registered in ClinicalTrials.gov, NCT03963388. Between March 1, 2019, and March 27, 2021, 214 patients were enrolled in the intervention group (n=109) or control group (n=105). At the primary timepoint, the adjusted mean difference in PDQ-39 was-2.0 in favour of the intervention group (95% CI-4.0 to 0.1); p=0.056). The intervention group scored better on the communication index score of the PDQ-39 (post hoc analysis), with an adjusted mean difference of-5.3 (95% CI-9.4 to-1.2; p=0.011). We found no between-group differences on any other PDQ-39 domain. Follow-up measurements showed a significant reduction of the PDQ-39 compared to the primary timepoint with a difference of 2.40 (95%CI 0.77-4.02; p=0.004). Personalised remote speech therapy improved communication-related quality of life, but not overall quality of life. Michael J. Fox Foundation, Gatsby Foundation, and Health∼Holland.