William Terrill is an expert in police behavior, with an emphasis on police use of force and police culture. 
Professor Terrill has worked with Phoenix Police Department to assess officer perceptions of firearm danger. Additionally, he has established a partnership between ASU and the Federal Law Enforcement Training Center (FLETC) in Glynco, Georgia, which provides internship opportunities for graduate students to gain valuable research experience.

Terrill is Interim Associate Dean in the Watts College of Public Service and Community Solutions, and Professor in the School of Criminology and Criminal Justice at Arizona State University.

His prior work has examined a number of issues, including the variation in use of force policies throughout the country, and the various outcomes associated with the different policies, as well as numerous police observational studies in several cities.