Justice Felix Reginald Dias Bandaranaike I (Sinhala:ෆෙලික්ස් රෙජිනල්ඩ් ඩයස් බණඩාරනායක) (26 July 1861 - 30 January 1947) was a Ceylonese (Sri Lankan) judge and lawyer. He was a Judge of the Supreme Court of Ceylon.