- April 1, 1971 (This strip is adapted in the segment "Charlie Brown and Lucy" of the 1983 The Charlie Brown and Snoopy Show episode "Snoopy the Psychiatrist")
- April 2, 1971 (This strip is adapted in Lucy Must Be Traded, Charlie Brown)
- April 3, 1971 (According to this strip, Charlie Brown is 8 years-old (1984 is a predicted future))
- April 4, 1971
- April 5, 1971
- April 6, 1971
- April 7, 1971
- April 8, 1971
- April 9, 1971 (The first reference to Helen Sweetstory)
- April 10, 1971
- April 11, 1971 (The first time that Snoopy is called the Easter Beagle. He had previously appeared as an Easter Bunny-like character on April 11, 1968 and March 29, 1970)
- April 12, 1971
- April 13, 1971
- April 14, 1971
- April 15, 1971
- April 16, 1971
- April 17, 1971
- April 18, 1971
- April 19, 1971
- April 20, 1971
- April 21, 1971
- April 22, 1971
- April 23, 1971
- April 24, 1971
- April 25, 1971
- April 26, 1971 (This strip is adapted in the segment "Sally" on It's an Adventure, Charlie Brown)
- April 27, 1971 (This strip is adapted in There's No Time for Love, Charlie Brown)
- April 28, 1971
- April 29, 1971
- April 30, 1971 (This strip is adapted in There's No Time for Love, Charlie Brown and in the segment "Sally" on It's an Adventure, Charlie Brown)
| ← March 1971 | May 1971 → |