8 Simple Rules is about a married couple with three children, set in a Detroit, Michigan suburb. The father, Paul Hennessy (John Ritter, Three's Company), is a sportswriter who is prompted by his wife Cate's (Katey Sagal, Married... with Children, Futurama) return to nursing to take a more active role in raising their two teenage daughters, Bridget (Kaley Cuoco), and Kerry (Amy Davidson), and their son Rory (Martin Spanjers). He is soon overwhelmed by the responsibility of being the father of teenage daughters and misses being a sports writer. Paul begins writing a column from home about his struggles with his children and offers advice to people who are in his same position. His teenage daughters are dating, which sparks the use of the "8 simple rules for dating my teenage daughter". The show, created by veteran comedy writer Tracy Gamble, derives its name and some of its elements from W. Bruce Cameron's book 8 Simple Rules for Dating My Teenage Daughter (ISBN 0-7611-2314-8).

The rules are:

1. Use your hands on my daughter and you'll lose them after.
2. You make her cry, I make you cry.
3. Safe sex is a myth. Anything you try will be hazardous to your health.
4. Bring her home late, there's no next date.
5. Only delivery men honk. Dates ring the doorbell. Once.
6. No complaining while you're waiting for her. If you're bored, change my oil.
7. If your pants hang off your hips, I'll gladly secure them with my staple gun.
8. Dates must be in crowded public places. You want romance? Read a book.

The third season took a creative turn, revolving more around Jim and C.J. than the Hennessy family, more specifically not revolving around the raising of the Hennessy girls. However this was little more than a phase in a way, and newly added characters joined the show as an ensemble, and shortly after their novelty wore off, the show found its roots once more.