Do I need to pass an Estonian language exam to get the long-term resident's permit?

The long-term resident's residence permit requires proficiency in Estonian at the B1 level. You can satisfy this by passing the official state language examination, or by having completed your basic, secondary, or higher education in the Estonian language.

There are exemptions from the language requirement, including for applicants who are under 15, over 65, or who have limited legal capacity. If you are not exempt, it is sensible to plan and prepare for the exam well ahead of your application.