Johannes "Jan" van Aswegen Steytler[1] (October 26, 1910 – after 1977) was a liberal South African politician and the first leader of the Progressive Party (PP).

On the outbreak of the Second World War, Steytler returned to South Africa to become a member of the Medical Corps of the Union Defence Force.

As a result of his increased prominence Steytler became the leader of the UP in Cape Province and tried to persuade his party to take a more liberal direction on racial issues.

[4] After failing to prevail within the UP leadership, Steytler became the leading figure in a group of progressives which eventually broke away to found a new party.

[5] Steytler was a powerful personality and a compelling orator, but like all Progressive MPs with the sole exception of Helen Suzman, he lost his seat in the South African parliament in the 1961 general election.