To help create an evidence base in Europe for effective interventions that improve the well-being of homeless people, we tested whether critical time intervention (CTI), a time-limited intervention developed to support vulnerable people during times of transition, is effective outside the United States. For this multicenter, parallel-group randomized controlled trial, 183 adults who were moving from shelters in the Netherlands to supported or independent housing were allocated to CTI or care-as-usual. The primary outcome was number of days rehoused, which was assessed by interviewing participants four times during a 9-month follow-up. Outcomes were analyzed with three-level mixed-effects models. The primary outcome did not differ between groups. CTI had a significant effect on family support and, for people experiencing less social support, psychological distress. Groups did not differ significantly on social support, fulfillment of care needs, quality of life, self-esteem, excessive alcohol use, or cannabis use. Because few participants were homeless at 9 months, more research is needed to establish whether CTI can prevent long-term recurrent homelessness. Given recent emphasis on informal support in public services and positive effects of CTI on family support and psychological distress, CTI is a fitting intervention for Dutch shelter services.