If it is a peony rather than a tree peony, maybe it is planted too deep. Have you put soil or compost on it, mulched or top dressed it? If you have.....then try scraping it away carefully. I don't think there will be any chance of flowering this season if you do this. Its up to you if you want to bring it nearer to the surface, if planted deep.....it might be quite large.

How old is it? My peony is 3 years old now (this is the 3rd summer after planting) and has produced one flower this year - nothing the previous years. I am hopeful that next year will be better. If it's a fairly young plant, it could just need time. If an old plant, then follow the advice above.