Background: Harmful alcohol consumption is a major global problem. An estimated 91 million people worldwide are negatively affected by their own alcohol use, and 2.2 million deaths are attributable to alcohol use every year. The societal costs of harmful alcohol consumption are estimated at 2.5% of GDP. Although evidence-based clinical guidelines have been developed, alcohol use disorder (AUD) remains undertreated in most countries.Objective: We examine the introductionof AUD national clinical guidelines in Denmark in 2015 on adherence and patient outcomes for patients with different socioeconomic characteristics and fortwo provider types: general practices (GPs) and specialised alcohol treatment centres (SATC).Methods: We use Danish administrative registry data of 7,488 patients receiving AUD treatment from GPs and 3,118 patients receiving treatment at SATCs between 2009 and 2018 linked with information on health care utilization and socioeconomic characteristics at the individual level. We estimate separate regressions on treatments for GPs and SATCs. We use linear probability models to estimate the change in treatment and subsequent health care utilization and outcomes for patients treated before versus after the introduction of the guidelines, controlling for patient characteristics and time trends. In sensitivity tests we include municipality fixed effects and GP or SATC fixed effects to account for unobserved heterogeneity relating to structural or institutional characteristics.Results: The introduction of clinical guidelines was associated with statistically significant increases in the use of evidence-based treatment for individuals treated of about 10 percentage points(p