jats:p The London 2012 Olympic and Paralympic Games are considered to have been a great success for the UK. In building the Olympic Park, another great achievement was the clean-up and reuse of a large area of contaminated land. A remediation project of this size would typically take 5 to 15 years to complete, but the project team completed the remediation work in less than 3 years. This study provides an in-depth examination of the remediation practices at the site, mainly from the perspective of sustainable construction. Data were collected from multiple sources, including project files, publications by various government agencies and non-governmental organisations, as well as qualitative interviews with project team members. The paper first presents a review of brownfield redevelopment and sustainable remediation literature. Sustainability initiatives and achievements in the Olympic Park site remediation project are summarised and discussed. These mainly included suitable remediation strategies, recycling and reuse of contaminated soil by using soil washing and innovative in situ remediation of contaminated groundwater through bioremediation. The paper identifies a number of challenges and lessons learned regarding brownfield remediation in megaprojects, which warrant further technological development and appropriate policy actions to address. </jats:p>