Lethbridge joined Commercial Bank in July 2017. In 2023, the Commercial Bank of Qatar reported $45.2 billion in total assets and a net profit of $827 million. It had a market value of $5.8 billion as of January 2024. Lethbridge was previously the CEO of ANZ Royal Bank, a joint venture of Australia and New Zealand Banking Group in Cambodia. She has been a board member of Alternatif Bank and Alternatif Lease company since 2018.