We conducted our review of the Science and Technology’s (S&T) insider threat program between January 2017 and June 2017. S&T is the primary research arm of the Department of Homeland Security (DHS). Its mission is to strengthen the Nation’s security and resiliency by providing knowledge products and innovative solutions to support DHS mission operations. Specifically, Congress created S&T in 2003 to conduct basic and applied research, development, demonstration, testing, and evaluation activities relevant to any or all elements of the Department. S&T oversees laboratories where scientists perform mission-critical research on chemical and biological threats, radiological and nuclear detection, animal diseases, transportation security, and explosives trace identification. S&T employees, contractors, and business partners—especially those with special or elevated privileges—can potentially use their inside knowledge and access to exploit vulnerabilities and cause harm to mission-critical systems and operations. We made nine recommendations that, if implemented, should strengthen S&T’s management of insider threat risks. The Department concurred with all of the recommendations.