The 1965–66 Shell Shield season was the inaugural edition of what is now the Regional Four Day Competition, the domestic first-class cricket competition for the countries of the West Indies Cricket Board (WICB).

The tournament was sponsored by Royal Dutch Shell, with matches played from 27 January to 14 March 1966.

Five teams contested the tournament – Barbados, British Guiana, Jamaica, Trinidad and Tobago, and a Combined Islands team (drawn from the Leeward and Windward Islands).

Jamaican batsman Easton McMorris and Barbadian bowler David Holford, led the tournament in runs and wickets, respectively.

The top five run-scorers are included in this table, listed by runs scored and then by batting average.