* 2021 Royal Society Elected fellow
* 2018 Gesellschaft Deutscher Chemiker Otto Roelen Medal
* 2017 UK Catalysis Hub Sir John Meurig Thomas Catalysis Medal
* 2016 Royal Society of Chemistry Corday-Morgan Prize
* 2015 WISE Campaign Research Award
* 2011 Bio-Environmental Polymer Society Outstanding Young Scientist Award
* 2009 Royal Society of Chemistry Energy, Environment and Sustainability Early Career Award
* 2005 Royal Society of Chemistry Meldola Medal and Prize
* 2001 Royal Society of Chemistry Laurie Verangno Award
Williams was appointed Officer of the Order of the British Empire (OBE) in the 2020 Birthday Honours for services to chemistry.