Colvin Reginald de Silva (1907 – 27 February 1989;[1] commonly known as Colvin R. de Silva) was a Sri Lankan Cabinet Minister of Plantation Industries and Constitutional Affairs, prominent member of parliament, Trotskyist leader and lawyer in Sri Lanka.

His father Obinamuni Arnolis de Silva, was a registered medical practitioner attached to the Department of Health.

He thereafter studied history at University College, Ceylon, gaining a BA from the University of London and went on to gain his PhD from King's College London in 1932 for his thesis: Ceylon Under the British Occupation, later published as a book.

From 1940s to 1960s Colvin R. de Silva enjoyed an unparalleled reputation as a criminal lawyer of great distinction.

In the Sathasivam murder case, his exceptionally brilliant cross-examining skills resulted in the acquittal of his client, while in the Kularatne murder case appeal, it was his intimate knowledge of the law of circumstantial evidence that saved the accused.

After the war he returned to Ceylon and became the main leader of the Bolshevik Samasamaja Party (BSP).

In 1952 he lost the Wellawatte-Galkissa seat to the United National Party candidate, S. de Silva Jayasinghe due to the unpopularity he gained for his role in the Sathasivam murder case, but regained it at the subsequent parliamentary elections in 1956.

In 1964 de Silva had urged against the LSSP joining the government, but unlike others who stood by that line he stayed in the party.

In 1987 he led a protest against the ban on May Day rallies in Sri Lanka and suffered a serious burn injury on one of his feet due to a tear gas cartridge that was thrown at the protesters by the police, which troubled him till his death.

[citation needed] He died a few days prior to taking his oath as an MP under new alliance on 27 February 1989 in Colombo.