A thesis committee (or, at some universities, specifically for the doctorate, a dissertation committee) is a committee that evaluates a student's thesis.

Although each school is different, for the master's degree the "committee" may be only one advisor, or perhaps a small group.

For a research-oriented doctorate such as the Ph.D., the process is considerably more involved. The committee is chosen by the student in conjunction with his or her thesis advisor. The members, which usually vary in number from two to four, are Doctors in their field and will have the task of reading the dissertation, making suggestions for changes and improvements, and sitting in on the defense. Depending on the subject matter, one may be a professor from a related field.

One of the most important steps in a doctoral program is assembling a good committee. If the student has members who have "issues" between them, he or she can be placed in a very difficult position. On the other hand, a good working committee whose members are well recognized in their field can be of considerable career help. Again, careful thought should go into this process.

The defense is the last hurdle in the attainment of a doctorate. At this final meeting, the doctoral candidate typically speaks for some amount of time on the dissertation, and then answers the questions of the members of the committee. At many universities, the candidate's talk is open to the public, who may ask questions, but are then asked to withdraw so that the committee may ask further questions in a closed session. (In the UK the defense is known as a viva, short for viva voce, Latin for "live voice".) If the defense is successful, the committee members and advisor sign the dissertation. The thesis committee can also require that final changes be made before the dissertation may be submitted to the graduate school. It is customary in many schools to grant the title of "Doctor" immediately following a successful defense by offering the words "Congratulations, Doctor..."