Question: who wrote it's a sin to tell a lie
Answer: `` It 's a Sin to Tell a Lie '' is a 1936 popular song written by Billy Mayhew , introduced early that year on records by many dance bands including Dick Robertson on the 78rpm record Champion 40106 , and later popularized by Fats Waller on Victor 25342 and re-issued on Victor 20 - 1595 , It was recorded in French by Cajun singer Cléoma Breaux in 1936 or 1937 .