This paper examines the impact of an environmental social marketing intervention on employees' energy saving intentions in a higher education institution (HEI) in the UK. The study examines the influence of both individual (attitudes, knowledge, norms) and organisational (perceived organisational behaviour, perceived organisational support) variables on intentions to save energy in the workplace. A quantitative methodology was used in the form of a survey, which also included open-ended survey questions. The quantitative data highlighted the important role of both general and specific attitudes in determining intentions. Additionally, data from the open-ended questions highlighted the importance of organisational behaviour, particularly support, policies and barrier reduction strategies in determining employees' pro-environmental intentions and behaviour. Differences were noted between employees in terms of their job roles (academic vs. non-academic) and job duration. In light of these findings, implications for sustainability in HEIs are discussed along with directions for future research.