Aim To evaluate the effects of a psychoeducational intervention compared with an education programme to strengthen quality of life, psychosocial adjustment, and coping in people with Parkinson's disease and their informal caregivers. Design A quasi-experimental study was performed with repeated measures at baseline, after the intervention and 6 months post-intervention. Methods The study was carried out at seven primary care centres from 2015-2017. A total of 140 people with Parkinson's and 127 informal caregivers were allocated to the experimental and the control groups. The experimental group received a 9-week psychoeducational intervention, whereas the control group received a 5-week education programme. Repeated measures ANOVA were used to test differences in quality of life, psychosocial adjustment, and coping between the experimental and control groups and over time. Results Patients and informal caregivers in both the experimental and control groups showed significantly better psychosocial adjustment at the post-intervention measurement compared with baseline data. We also found significantly greater quality of life in patients and coping skills in caregivers after the end of the interventions in the experimental and control groups. Nevertheless, no significant differences were identified on the outcomes at the 6-month post-intervention measurement. Conclusion The effect of the psychoeducational intervention was not different from the effect of the education programme. The strategies applied in both interventions followed a group approach led by a multidisciplinary team covering information about PD, healthy lifestyles, and social resources. They might be easily sustained in Primary Care to improve care for people with Parkinson's and informal caregivers.