Geographically: Yes. The Isle of Man sits in the Irish Sea, part of the British Isles archipelago off the northwest coast of mainland Europe. It lies between Great Britain (east) and Ireland (west), at 54°N, 4°W.
Politically: It's complicated.
The island has its own parliament (Tynwald, claimed as the world's oldest continuous legislature), government, legal system, and tax regime. The UK handles defense and international representation by convention. The British monarch is head of state, represented by a Lieutenant Governor.
"Europe" can mean the continent, the EU, or the cultural sphere. The Isle of Man is geographically European, culturally British/Celtic, but politically distinct from both the UK and EU.
In summary: On the map, it's in Europe. In law, it's a unique Crown Dependency.