Unanimously endorsed by the UN Human Rights Council in June 2011, the UN Guiding Principles on Business and Human Rights were the result of extensive consultations and debate about businesses’ status as human rights actors. Individual lawyers and legal experts were central to this process. The Guiding Principles establish that all businesses – not just states – have an explicit role in the realisation of human rights through a worldwide responsibility to respect them and provide guidance on how businesses can actually implement such respect. Since then, hundreds of multinational businesses have publicly committed to respecting human rights consistent with the Guiding Principles, not only for ethical reasons, but also to protect themselves from potential liability, negative public relations and the damaging reputational impact of civil society campaigns. This guide focuses on three areas that were identified at the meeting we convened, in late 2011, to start a discussion about the unique challenges law firms face as they adopt business practices consistent with the Guiding Principles. Part 1 examines the import of the Guiding Principles for lawyers. Part 2 introduces how firms can put their human rights responsibilities into practice when working for clients. Part 3 examines the relationship between professional codes of conduct for lawyers and the Guiding Principles and explores how the codes could further support the Guiding Principles.