Siobhan Toohill
BSc (Arch), BArch, GradDip Urban Design, MAICD
Non-executive Director
Siobhan is a pioneering leader in sustainability with over 20 years’ experience leading environmental, social and governance programs in ASX50 companies, focusing on climate, nature, human rights and social change.
As Westpac’s first Chief Sustainability Officer, Siobhan led the bank’s sustainability strategy, establishing science-based climate targets and approach to natural capital, and developing Australia’s first substantive Sustainable Finance Framework. She was a member of the governing body of the UN’s Net Zero Banking Alliance and was Co-chair of the UN Environment Program Finance Initiative’s Banking Board overseeing the UN Principles for Responsible Banking.
Siobhan currently serves as a Non-Executive Director of Landcom and The Social Outfit, and is a Trustee of Greater Sydney Parklands. Her advisory roles include member of the Australian Government’s Nature Repair Committee, NSW Anti-slavery Commissioner’s Advisory Panel, Alphinity Investment Management’s Sustainability Compliance Committee and NSW Councillor, Australian Institute of Company Directors.
Siobhan holds qualifications in science, architecture and design from Sydney University, has completed executive education at Stanford and INSEAD, and is an Adjunct Fellow with UNSW’s Centre for Social Impact. She was recognised as the banking winner in the 2024 AFR Women in Leadership Awards.
Siobhan has been appointed as a Director on the Board of Mulloon Institute in November 2025.
