Ruth Van Roekel McGregor (born April 4, 1943) is an American lawyer and former justice of the Arizona Supreme Court.
McGregor served as law clerk to Supreme Court of the United States justice Sandra Day O'Connor from 1981 to 1982 and served on the Arizona Court of Appeals from 1989 to 1998.
McGregor was appointed to the Arizona Supreme Court in 1998 by Governor Jane Dee Hull and remained there until her retirement in 2009.
She served a term as chief justice that ended with her retirement from the court.
McGregor is an advocate of Arizona's version of the Missouri Plan for choosing state judges.