In Jain diet, olives can be eaten if they are plain and vegetarian.

But pizza is only suitable if it has:

• no onion, garlic, potato, or other root vegetables
• no meat, egg, or fish ingredients
• no non-Jain cheese or animal rennet
• no contamination with non-vegetarian food, if you follow strict Jain practice

So, olives on Jain-friendly pizza can be eaten.