Leo Thomas Nimsick (January 26, 1908 – February 8, 1999) was a miner and political figure in British Columbia. He represented Cranbrook from 1949 to 1966 and Kootenay from 1966 to 1975 in the Legislative Assembly of British Columbia as a Co-operative Commonwealth Federation and then New Democratic Party member.
He was born in Rossland, British Columbia, the son of Thomas Nimsick and Anna Caesar. In 1934, he married Marie K. Zimmer. Nimsick worked at diamond drilling and dairy farming; he later worked for Cominco for 40 years, retiring in 1968. He served four years as an alderman for Rossland. Nimsick ran unsuccessfully for a seat in the provincial assembly in 1937. He ran for the leadership of the CCF in 1956, coming second to Robert Strachan. Nimsick later served in the provincial cabinet as Minister of Mines and Petroleum and as Minister of Travel Industry.
He died in 1999 at the age of 91.