This research represents one of the first qualitative studies to investigate fatigue in the tunnelling sector of the construction industry. It explores the opinions of tunnellers and their managers about how fatigue influences or is influenced by tunnelling, and how this is managed. Fatigue and sleepiness were discussed in six focus groups with frontline workers (n = 42) and 10 manager interviews. Fatigue was seen to be a problem, with all participants having experienced, or recognised in others, the feeling of sleepiness whilst at work. Fatigue and sleepiness are not commonly discussed between tunnelling workers and they do not feel comfortable reporting instances of fatigue. The research shows that workers in the tunnelling construction sector are exposed to a wide range of occupational factors that potentially increase their vulnerability to fatigue, including the physical environment, repetitive and monotonous tasks, variable shift patterns and manual work. Additionally, personal factors such as social and family demands, long commute times and living away from home, can increase the risk of fatigue. The construction industry in general has gone some way to address fatigue and there is opportunity to further improve fatigue management. However, a major shift is needed before workers will feel able to openly discuss fatigue with their employer.