%X Projection stabilization applied to general Lagrange multiplier finite element methods is introduced and analyzed in an abstract framework. We then consider some applications of the stabilized methods: (i) the weak imposition of boundary conditions, (ii) multiphysics coupling on unfitted meshes, (iii) a new interpretation of the classical residual stabilized Lagrange multiplier method introduced in Barbosa and Hughes, Comput Methods Appl Mech Eng 85 (1991), 109–128. © 2013 The Authors. Numerical Methods for Partial Differential Equations Published by Wiley Periodicals, Inc. 30: 567–592, 2014 %O © 2013 The Authors. Numerical Methods for Partial Differential Equations Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. %L discovery1384702 %K Lagrange multiplier method; Nitsche's method; stabilized finite element method %J NUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS %P 567 - 592 %D 2014 %A E Burman %V 30 %T Projection Stabilization of Lagrange Multipliers for the Imposition of Constraints on Interfaces and Boundaries %N 2