Iran Responsible Reporting Act of 2018 This bill amends the Iran Threat Reduction and Syria Human Rights Act of 2012 to require that reports on diplomatic efforts concerning Iran include information about efforts by other countries to sanction Iran for human rights violations and support for terrorist organizations, including Hamas and Hezbollah. The Department of State may host an annual summit with Iran's major trading partners to identify and take appropriate actions regarding front companies and funding mechanisms of Iran's Revolutionary Guard Corps. (Major trading partners of Iran are European Union member countries, China, India, and other countries that have a trade relationship with Iran exceeding $500 million in the most recent calendar year for which data is available.)