Background: Evidence to evaluate the efficacy and effectiveness of alcohol brief interventions is weakened by variability in measured outcomes and inconsistent reporting. This ongoing systematic review forms part of the larger Outcome Reporting in Brief Intervention Trials: Alcohol (ORBITAL) project aligned with the INEBRIA special interest group of the same name. The review aims to identify outcomes and wider domains used in efficacy and effectiveness trials of alcohol brief interventions. Materials and Methods: An ongoing systematic review and narrative synthesis of efficacy and effectiveness trials of alcohol brief interventions from 10 databases from Jan 2000–Sept 2016 (including EMBASE, MEDLINE, PsycINFO, CINAHL, Web of Science) and grey literature sources (including databases and trial registries). Alcohol brief intervention definitions are informed by National Institute of Clinical Excellence Public Health Guideline 24: Alcohol use disorders: prevention. The review was conducted in accordance with the Centre for Reviews and Dissemination (CRD) guidance and pre-registered on PROSPERO (CRD42016047185). Results: From the initial search of databases around 320 studies were identified, with the grey literature search ongoing. In the first 95 studies included, there were seven different overarching domains used to summarize the outcomes; biomarkers, alcohol consumption (includes problems, hazardous, harmful, or risky drinking), economic factors and resource use, health measures, life impact, intervention factors, and psychological factors. Preliminary findings suggest the most commonly reported were consumption outcomes such as frequency of drinking (9.3% of 486 outcomes), frequency of heavy drinking (8.6%), typical drinks on occasion (10%) and number of drinks in a week (8.4%). Fewest reported included economic factors and resource use, life factors (such as quality of life), and biomarkers. Conclusions: These preliminary findings indicate, as expected, considerable variability in the outcomes reported in alcohol brief intervention trials. Whilst it is perhaps unsurprising that consumption is the most common domain measured, there was considerable variability in how this is described as an outcome, and even more variability in how it is measured in practice. This illustrates the challenges in synthesizing the literature, and the need for a core outcome set to help alcohol brief interventionists to determine the minimum measurement standard for research and evaluation.