William Henry Peter Barber (10 September 1857 – 15 January 1943) was a New Zealand Member of Parliament for Newtown in Wellington.

He began work in his father's dyeing firm of Barber and Company, and eventually became its head.

His favourite idea was one shared by the other New Liberals-that the institutions of local government should be strengthened and given more scope and power.

He heartily supported Harry Ell's 1904 Municipal Corporations Bill, which provided for borough councils to hold referendums.

[4] He was a member of the Hutt Valley Electric Power Board (retired 1933); director of Wellington Deposit and Mortgage Company; chairman of the Wellington College Board of Governors (1924–31) and a member of the Kauri Timber Royal Commission.