This thesis investigates the roles of individual, household and country in individuals’ proenvironmental behaviours and aims to understand the relationship between environmental attitudes and behaviours using a multilevel modelling approach. The first and second papers analyse factors influencing individuals’ environmental behaviours in the United Kingdom using data from Wave 4 of the Understanding Society, UK Household Longitudinal Study. General environmental behaviour, as well as home-, transport- and purchasing-related behaviours are studied. The main focus is to highlight the role of the household on these individual behaviours. To account for the complex hierarchical structure of the survey data, where households are clustered within interviewers and geographical areas, both studies propose, for the first time, a cross-classified multilevel modelling approach. Results show that household, interviewer and area have significant effects on the reported environmental behaviours. The findings also suggest that individuals’ personal and environmental values have significant impacts on their behaviours. The third paper examines cross-national differences in individuals’ environmental behaviours by exploring how individual- and country-level factors influence their behaviours and how the relationship between personal environmental attitudes and behaviours varies across countries using a multilevel modelling approach. Analysis is conducted on the 2010 Environmental module of the International Social Survey Programme, a cross-national survey that deals with environmental behaviours and attitudes. General environmental behaviour, as well as home-, purchasing-, transport- and recycling-related behaviours are considered. Results show that both individual- and national-level variables have substantial effects in explaining different types of environmental behaviours. The inclusion of the random slope on environmental attitude also provides evidence that the effects of individuals’ environmental attitudes on their environmental behaviours vary significantly across nations.