Why does my Blender character deforms different in Unity

Hello, i have a character model rigged and animated in blender and it works fine in unity except of one little problem. He deforms a bit differently in unity.
Here is an example

I think it has something to do with the weight painting but i am not sure.

Just found out the answer to my own problem.Just navigate to:
Edit->Project settings->Quality->Other->Blend Weights
and change the number of bones.

Thank you for providing this! I have been working myself to the point of madness trying to fix ugly deforms in unity. I always assumed it was a problem on blenders side, and i`ve made more rigs than i can count, trying to solve the problem.
Nothing worked, but this fixed it! Thank you.