Place eggs in a saucepan and fill with cold water to cover. Bring to a boil over medium-high heat. Cover, remove from heat, and let stand for 15 to 20 minutes. Drain and run under cold water until chilled.

Peel the chilled hard-cooked eggs and place them in a bowl. Use a fork or potato masher to mash the eggs until finely chopped.

Stir in yogurt, mayonnaise, Dijon mustard, salt, and pepper until smooth. Add celery and green onion and combine well.