The environmental sustainability of hotel operations is increasingly scrutinized by hotel management and other stakeholders. This chapter discusses how the 'external influences' impact the pro-environmental behaviour of business travellers. Business travellers are particularly suited for the discussion in this chapter, because work duties - an external influence - are expected to impact traveller's behaviour. The mental and physical strain of travelling negatively impacted the attitudes towards travelling of the interviewed business travellers. After a brief discussion of literature on business travel, and an explanation of the methodology, the chapter focuses on traveller's attitudes to travelling and staying in hotels and the impact of these attitudes on environmental behaviour. Attitudes towards travelling for work differed considerably among travellers. The findings imply that the willingness of hotel guests to participate in environmental practices is not solely based on the availability of practices or the motivations of guests, but also on other factors that influence their behaviour.