Assuming you mean some kind of Osmanthus.

Here are possible reasons...I am assuming the plant seems to be otherwise growing well.

1) not established enough - wait a couple more years. I would say 3 years is the average time for mine to bloom, some slower growing cultivars ('Sasaba') took 4 or 5. O x fortunei will bloom the fastest, probably. Mine bloomed when it was a small 18"/.5 m plant.

2) too much shade

3) too much nitrogen fertilizer

4) watering or rainfall regime not to its liking...the common ones come from summer-wet climates

5) severe lack of phosphorus in the soil: this is unlikely but if you're in some odd part of the world like I dunno, the outskirts of Adelaide, Australia, it cannot be ruled out.

Bela, you aren't trying to grow your Osmanthus fragrans inside as a houseplant, are you?

Where are you located?