The International Lymphoma Radiation Oncology Group (ILROG) was founded in 2010 by a group of radiation oncology experts from several countries who are recognized as international academic leaders in the field of lymphoma. They explored the interest of radiation oncologists in the mission of the organization and were strongly encouraged by supportive responses from over 750 radiation oncologists spread across 40 different countries. They organized a group of 24 expert lymphoma radiation oncologists representing 14 countries, spanning from Asia to North America, to serve as a steering committee and to elect a chairman and vice chair. The Steering Committee agreed to focus first on establishing, harmonizing, and distributing new guidelines that would address the recent dramatic changes in the field principles, dose, and technological advances in radiotherapy of lymphoma. Their present goal is to enable and encourage the many radiation oncologists interested in lymphoma to join ILROG as members and engage in accomplishing the objectives outlined below through active participation in newly set committees, research, and special mission teams.