This is a question that you must be extremely careful with. The person who is interviewing you for the current job may very well be your future supervisor so they are looking for some critical information in your response to this question.
Your answer needs to demonstrate that you have a solid understanding of what makes a good supervisor. By asking this question the interviewer is attempting to discover how you respond to supervision and what they can expect if they should hire you for the open position.
Therefore, it is critical to carefully prepare an answer to this type of question. Remember that you never want to say anything negative about a former supervisor because the interviewer will naturally assume that if you are willing to discuss a former boss negatively that you might do the same to them if they should hire you for the job. Instead, you want to focus on discussing the good qualities of a former supervisor that you performed well under. For example, you might say that he or she was a good supervisor because they had an open door policy and supervised staff with a balanced and fair approach.
It can be difficult to know what the supervisory policy is in the company where you are interviewing and exactly what they are looking for in your response, so to some degree your response to this question should be somewhat generic. You should not go into a lot of details when you are answering this question because becoming too detailed in your response can lead you into trouble.
Instead, focus on describing a supervisor that you felt was fair and supportive. Keep in mind that you never want to leave the impression with your response that you carry a grudge or that you assess blame in any way. The key is to make sure that you indicate what you were able to learn from a supervisor. This reflects well on you and demonstrates to the employer that you are willing to listen and have a desire to learn in order to improve your abilities. Ultimately, the interviewer is not seeking information about your former bosses but more importantly information about you. Keep this in mind and you will be able to handle this question without any problems.