Westminster City Council, the local authority of the City of Westminster in London, England, is elected every four years. Since the last boundary changes in 2002, 60 councillors have been elected from 20 wards. New boundary changes will come into effect for the 2022 elections, when the borough will be represented by 54 councillors in 18 three-member wards.
 From the first elections to the council in 1964 until 2022, overall political control of the council was held by the Conservatives, with Labour gaining control in 2022:
 The role of Lord Mayor of Westminster is largely ceremonial, with political leadership instead being provided by the leader of the council. The leaders since 1964 have been:
 There were no by-elections.
 There were no by-elections.
 The by-election was called following the resignation of Michael B. Forsyth.
 The by-election was called following the resignation of Francis Maude.
 The by-election was called following the death of Jean Merriton.
 The by-election was called following the resignation of Peter J. Hartley.
 The by-election was called following the resignation of Rachel E. Whittaker.
 The by-election was called following the resignation of Patricia M. Kirwan.
 The by-election was called following the resignation of Barry C. Legg.
 The by-election was called following the resignation of Shirley Porter.
 The by-election was called following the resignation of Joseph Glickman.
 The by-election was called following the death of Hugh G. Garside.
 The by-election was called following the resignation of Peter C. S. Bradley.
 The by-election was called following the resignation of Karen P. Buck. 
 The by-election was called following the resignation of Andrew H. Dismore.
 The by-election was called following the resignation of Nicola Russell.
 The by-election was called following the resignation of Richard A. Stirling-Gibb.
 The by-election was called following the resignation of Ron M. Harley.
 The by-election was called following the resignations of  Jillian A. Selbourne and Gary P. Martin.
 The by-election was called following the resignation of Jonathan S. Djanogly.
 The by-election was called following the resignation of Josephine S. Ohene-Djan.
 The by-election was called following the death of Kevin A. Gardner.
 The by-election was called following the resignation of Michael G. Vearncombe.
 The by-election was called following the death of Antony G. Mothersdale.
 The by-election was called following the resignation of Simon H. Milton.
 The by-election was called following the death of Ian G. Wilder.
 The by-election was called following the death of Mushtaq A. Qureshi.
 The by-election was called following the resignation of Colin Barrow.
 The by-election was called following the resignation of Harvey C. J. Marshall.
 The by-election was called following the resignation of Edward J. C. Argar.
 The by-election was called following the resignation of Nilavra Mukerji.
 The by-election was called following the death of Audrey R. Lewis.
 The by-election was called following the resignation of Vincenzo Rampulla.
 The by-election was called following the resignation of Robert J. Davis.
 The by-election was called following the resignation of Andrea Mann.