This chapter considers some of the legal and professional implications of social media use. These are discussed from two perspectives: firstly, how the law is changing to help ensure harmful and false information is not distributed, and secondly how professionals should responsibly use social media. To illustrate each of these, the chapter focuses on proposed reforms to the UK law and the UK General Medical Council’s (GMC) guidance for doctors. The principles discussed will apply to other jurisdictions and professional groups, but individual professionals should ensure they are familiar with the frameworks within which they practise.