We aimed to test a mindfulness-based psychoeducation group (MBPEG), v. a conventional psychoeducation group (CPEG) v. treatment as usual (TAU), in patients with schizophrenia-spectrum disorders over a 24-month follow-up.This single-blind, multi-site, pragmatic randomized controlled trial was conducted in six community treatment facilities across three countries (Hong Kong, mainland China and Taiwan). Patients were randomly allocated to one of the treatment conditions, and underwent 6 months of treatment. The primary outcomes were changes in duration of re-hospitalizations and mental state (Positive and Negative Syndrome Scale; PANSS) between baseline and 1 week, and 6, 12 and 18 months post-treatment.A total of 300 patients in each country were assessed for eligibility between October 2013 and 30 April 2014, 38 patients per country (n = 342) were assigned to each treatment group and included in the intention-to-treat analysis. There was a significant difference in the length of re-hospitalizations between the three groups over 24 months (F 2,330 = 5.23, p = 0.005), with MBPEG participants having a shorter mean duration of re-hospitalizations than those in the other groups. The MBPEG and CPEG participants had significant differential changes in proportional odds ratios of complete remission (all individual PANSS items <3) over the 24-month follow-up (37 and 26%, respectively), as opposed to only 7.2% of the TAU group (χ2 = 8.9 and 8.0, p = 0.001 and 0.003, relative risk = 3.5 and 3.1, 95% confidence interval 2.0-7.2 and 1.6-6.3).Compared with TAU and CPEG, MBPEG improves remission and hospitalization rates of people with schizophrenia spectrum disorders over 24 months.