This House of Lords Library Briefing is the result of an initiative by the Parliamentary Office of Science and Technology to foster collaborative work between academics and Parliament. As part of this scheme, the House of Lords Library hosted Dr Ruth Dixon of the Blavatnik School of Government, University of Oxford, to explore the impact of the House of Lords, focusing on the chamber’s legislative role. In this briefing, Dr Dixon describes how she used her novel methodology to analyse amendments to government legislation in the most recent completed parliamentary session, 2016–17. This analysis is followed by two case studies which explore interactions between the Government and legislators during the same session. The first outlines the response of Parliament in April 2017 to the unexpected announcement of a general election. The second analyses the fate of part of the Children and Social Work Act 2017: clauses that were intended to allow local authorities to apply to be exempted from statutory provisions in children’s social care. Overall Dr Dixon concludes that the impact of the House of Lords is relatively subtle. In order to influence policy through legislation, Members must not only gather cross-party support within the chamber, they must also gain the support of the Commons. Her analysis shows various ways in which this is achieved.