Peter Sinclair (November 18, 1819 – October 9, 1906) was a Scottish farmer and politician in Prince Edward Island.

He represented Queen's County in the House of Commons of Canada from 1873 to 1878 as a Liberal member.

He was born in Glendaruel, Argyleshire, the son of Peter Sinclair, and came to Queens County, Prince Edward Island in 1840 with his mother.

Sinclair represented 1st Queens in the Legislative Assembly of Prince Edward Island from 1867 to 1873 and from 1882 to 1900 as a Liberal.

He served in the Executive Council for the province as government leader from 1872 to 1873 and as minister without portfolio from 1891 to 1898.