Whilst representations of old age and older people in traditional media have been well documented, examinations of such representations within social media discourse are still scarce. This is an unfortunate omission because of the importance of social media for communication in contemporary society. In this study, we combine content analysis and discourse analysis to explore patterns of representation on Twitter around the terms ageing, old age, older people and elderly with a sample of 1,200 tweets. Our analysis shows that ‘personal concerns/views’ and ‘health and social care’ are the predominant overall topics, although some topics are clearly linked with specific keywords. The language often used in the tweets seems to reinforce negative discourses of age and ageing that locate older adults as a disempowered, vulnerable and homogeneous group; old age is deemed a problem and ageing is considered something that needs to be resisted, slowed or disguised. These topics and discursive patterns are indeed similar to those found in empirical studies of social perceptions and traditional media portrayal of old age, which indicates that social media and Twitter in particular appears to serve as an online platform that reproduces and reinforces existing ageist discourses in traditional media that feed into social perceptions of ageing and older people.