This thesis present three studies that aim to investigate and compare different definitions of standard drinks and alcohol intake recommendations worldwide and explore University students' knowledge of, attitudes toward, and use of unit-based guidelines in the UK. Excessive alcohol consumption is associated with a range of economic, social and health problems. Heavy drinking patterns among University students are well documented. Like most developed countries, the UK government introduced the “sensible drinking” message and guidelines for alcohol consumption to encourage people to reduce their drinking. The first study was a review of official definitions of standard drinks and guidelines of 57 countries. Analyses showed a lack of international consensus in terms of the size of “standard drinks” or recommended daily or weekly maximum alcohol intake. The results suggested that a global system of units and low risk drinking guidelines could help people make better-informed choices about alcohol consumption and help consistency among researchers, health professionals and governments developing public health initiatives. The second study used an online survey to examine the multivariate correlates of motivation to use guidelines and accuracy of estimates of alcohol consumption among 640 students aged 18-37. Results showed that motivation and ability to accurately estimate the unit content of beverages were linked to various cognitive and behavioural variables such as conscientiousness and extraversion, familiarity with, and frequency of use of the guidelines and perceptions of how easy and useful the unit-based guidelines are. The third study employed semi-structured interviews in a sample of 12 students selected from the second sample. Thematic analysis revealed that participants were not motivated to adhere to the guidelines and lacked skills to apply them to manage their own drinking. Findings suggest that multifaceted public health interventions should include provision of information, efforts to motivate young people to change their behaviour, and strategies to develop skills for managing alcohol consumption.