A deputy leader (in Scottish English, sometimes depute leader) in the Westminster system is the second-in-command of a political party, behind the party leader. Deputy leaders often become Deputy prime minister when their parties are elected to government. The deputy leader may take on the role of the leader if the current leader is, for some reason, unable to perform their role as leader. For example, the deputy leader often takes the place of the party leader at question time sessions in their absence. They also often have other responsibilities of party management.

• Sussan Ley, Deputy leader of the Liberal Party of Australia
• Richard Marles, Deputy leader of the Australian Labor Party
• Perin Davey, Deputy leader of the National Party of Australia
• Nick McKim and Larissa Waters, Deputy leaders of the Australian Greens

• Vacant, Deputy leader of the Liberal Party of Canada
• Ang Davidson, Deputy leader of the Green Party of Canada
• Melissa Lantsman and Tim Uppal, Deputy leaders of the Conservative Party of Canada
• Alexandre Boulerice, Deputy leader of the New Democratic Party

• Sol Mamakwa, Deputy leader of the Ontario New Democratic Party

• Helen McEntee, Deputy leader of Fine Gael
• Jack Chambers, Deputy leader of Fianna Fáil
• Michelle O'Neill, Vice president of Sinn Féin
• Róisín Garvey, Deputy leader of the Green Party
• Gemma Brolly, Deputy leader of Aontú

• Nicola Willis, Deputy leader of the National Party of New Zealand
• Kelvin Davis, Deputy leader of the New Zealand Labour Party
• Fletcher Tabuteau, Deputy leader of New Zealand First
• Brooke van Velden, Deputy leader of ACT New Zealand

• Angela Rayner, Deputy leader of the Labour Party
• Daisy Cooper, Deputy leader of the Liberal Democrats
• Amelia Womack, Deputy leader of the Green Party of England and Wales

• Keith Brown, Depute leader of the Scottish National Party^[1]
• Jackie Baillie, Deputy leader of the Scottish Labour Party
• Alistair Carmichael, Deputy leader of the Scottish Liberal Democrats

• Carolyn Harris, Deputy leader of the Welsh Labour Party
• Rhun ap Iorwerth & Siân Gwenllian, Deputy leaders of Plaid Cymru
• Christine Humphreys & Kirsty Williams, Deputy leaders of the Welsh Liberal Democrats
• Duncan Rees & Lauren James, Deputy leaders of the Wales Green Party

• Vacant, Deputy leader of the Democratic Unionist Party
• Vacant, Deputy leader of the Social Democratic and Labour Party
• Eóin Tennyson, Deputy leader of the Alliance Party of Northern Ireland
• Mal O'Hara, Deputy leader of the Green Party in Northern Ireland