This publication makes the case for working with men <span class="attribute-to-highlight medbox">and</span> women, boys <span class="attribute-to-highlight medbox">and</span> girls, together in an intentional <span class="attribute-to-highlight medbox">and</span> mutually reinforcing way that challenges gender norms in the pursuit of improved health <span class="attribute-to-highlight medbox">and</span> gender equality. In addition to providing a definition for the new concept of gender synchronization, this document provides examples of synchronized approaches that have worked first with women <span class="attribute-to-highlight medbox">and</span> girls, or first with men <span class="attribute-to-highlight medbox">and</span> boys, <span class="attribute-to-highlight medbox">and</span> describes interventions that have worked with both sexes from the start. It also provides examples of new <span class="attribute-to-highlight medbox">and</span> emerging programs that should be watched in the coming years for the knowledge they may contribute to the implementation of gender synchronization.