- Cornuelle's Law: Authority tends to assign jobs to those least able to do them.
- Courtois's Rule: If people listened to themselves more often, they would talk less.
- Dale's Parking Postulate: If only two cars are left in a vast parking lot, one will be blocking the other.
- Darrow's Comment: History repeats itself. That's one of the things wrong with history.
- Davis's Law: If a headline ends in a question mark, the answer is "no".
- Deal's First Law of Sailing: The amount of wind will vary inversely with the number and experience of the people you take on board.
- Deal's Second Law of Sailing: No matter how strong the breeze when you leave the dock, once you have reached the furthest point from port the wind will die.
- Dedera's Law: In a three-story building served by one elevator, nine times out of ten the elevator car will be on a floor where you are not.
- DeHay's Axiom: Simple jobs always get put off because there will be time to do them later.
- De Jesus's Observation: An expert is that person who is most surprised by the latest evidence to the contrary.
