Alcohol use disorder (AUD) is one of the most common psychiatric disease in the general population, characterized by having a pattern of excessive drinking despite the negative effects of alcohol on the individual’s work, medical, legal, educational, and/or social life. Currently, the bio-psycho-social model describes properly AUD as a multidimensional phenomenon including biological, psychological, and socio-cultural variables affecting the nature, maintenance, and expression of the disorder. The AUD diagnostic process is crucial since the treatment success depends heavily on the accuracy and the adequacy of the diagnosis. The diagnosis is based on a comprehensive assessment of the patient’s characteristics and uses interviews and psychometric instruments for collecting information. This paper will provide insights into the most important psychological dimensions of AUD and on the best psychometric instruments for proposing AUD diagnosis.