Sir William Johnson, CMG, CBE, QPM was an eminent English police officer.
Johnson joined Portsmouth City Police in 1920. In 1932 he was appointed as Chief Constable of Plymouth City Police. He became Assistant Chief Constable of Birmingham City Police in 1936, and was appointed Chief Constable in 1941. He served with Her Majesty's Inspectorate of Constabulary from 1945 to 1963: for the last two years of this period he was its inaugural Chief.