Reginald Walter Michael "Mickey" Dias Bandaranaike QC (3 March 1921 – 17 November 2009) was a barrister, academic and author of leading works on jurisprudence and the law of tort.

Born in Colombo, Ceylon (now Sri Lanka) on 3 March 1921 to the Dias family which had strong connections to the law.

His father was Felix Reginald Dias Bandaranaike II, puisne justice, and his mother was "Princess" Joy De Livera.

[1] He attended the Ceylon Law College and in 1939, entered Trinity Hall, University of Cambridge, like his father and grandfather before him.

He continued to work from Trinity Hall until elected by Magdalene College, Cambridge, as their first Law Fellow in 1955 going on to hold office as president from 1988 to 1991 and serving as secretary to the Faculty Board of Law, as a member of the General Board and the Council of the Senate, and as Senior Proctor 1987–88.