This bill, titled the DHS Special Events Program and Support Act, amends the Homeland Security Act of 2002 to establish a new program within the Department of Homeland Security. This program is designed to assess the threat, vulnerability, and consequences of terrorism or other security threats at pre-planned special events that are not designated as National Special Security Events. It creates a standard process for Federal, State, local, Tribal, and territorial officials to voluntarily request a special event rating from the Secretary of Homeland Security. The program will utilize a risk-based methodology to evaluate these requests, considering factors such as anticipated attendance by officials or dignitaries, event size, credible threats, and other relevant homeland security information. Based on these ratings, the Secretary is authorized to provide security and situational awareness support to requesting officials. Furthermore, the bill mandates annual reports to Congress on program activities and requires the Department to conduct research and development into technologies for enhancing security at mass gatherings, while upholding constitutional and civil liberties protections.