The question refers to "Coke Zero," so, no, Coke Zero does have caffeine. A 12-ounce can of Coke Zero contains 34 mg of caffeine.
Here's a comparison of caffeine content between Coke Zero and Diet Coke, according to Tasting Table:
| Beverage | Caffeine (mg per 12 oz) |
|---|---|
| Diet Coke | 46 |
| Coke Zero | 34 |
