Organization of American States Legislative Engagement Act of 2018 This bill directs the Department of State of State to establish procedures for the Organization of American States (OAS) that: increase the participation of elected national legislators from OAS member states in OAS activities, including activities that advance the principles of the Inter-American Democratic Charter; create an annual forum for the presidents of such legislatures to discuss issues of hemispheric importance, including efforts to combat corruption and defend human rights; permit such legislators to make presentations and provide expert advice to the OAS Secretariat, OAS Permanent Council, and OAS General Assembly; and strengthen OAS Secretariat programs that provide technical assistance for legislative modernization. The State Department shall: carry out diplomatic efforts to secure political and financial support for such procedures, and submit to Congress a strategy for supporting OAS anti-corruption and human rights promotion efforts.