Despite work to prevent and reduce homelessness over the last 15 years, the number of homeless persons in Norway has remained stable since the first mapping of homelessness was published in 1997. We conducted a systematic review on the effectiveness of housing programs and case management to improve housing stability and reduce homelessness among people who are homeless or at-risk of becoming homeless. The key findings show that high intensity case management is probably better than usual services at reducing the number of people who are homeless. The program called Housing First is probably better than usual services at reducing homelessness, improving housing stability and increasing the amount of time in housing.