I would love to know the circumstances under which people opt for a second doctorate degree.

  • Could a professor working in a university write up a thesis and submit it to his department to earn a second doctorate?

  • Do only those who want to remain in the university forever as students go for a second doctorate?

  • Are there any general merits/downsides to earning 2 PhDs, if you are perhaps assured of a research career after a good first one?

  • 35
    I know someone who has 3 professorships and 2 doctorates. His title is Prof. Prof. Prof. Dr. Dr. Jun 1, 2012 at 8:32
  • 19
    "Are there any general merits/downsides to earning 2 PhDs, given you are assured of a research career after a good first one?" The premise is very questionable: a good PhD by no means "assures" a research career. Jun 1, 2012 at 16:26
  • 18
    You go for a double doctorate when your first postdoc ends and you still haven't found a job, and you're fine with living off a stipend for another five years.
    – eykanal
    Jun 1, 2012 at 16:51
  • 37
    @DaveClarke: Excuse me, but that's Herr Professor Professor Professor Doktor Doktor.
    – JeffE
    Jun 2, 2012 at 5:52
  • 6
    There are some departments at certain schools that won't even accept you to their PhD programs if you already have a PhD.
    – cartonn
    Apr 11, 2013 at 20:11

5 Answers 5


Generally you cannot get two PhDs in the same field. One could get a second PhD in a second field.

People who want to do research in multiple fields or in a multidisciplinary topic or wish to change fields may obtain multiple PhDs. Alternatively, as you suggest, people who want to remain students forever do that.

The main downside of doing multiple PhDs is that people may not see that you are moving on with your career. There is a career after getting your PhD, and obtaining a PhD is a small step along that career path. Hovering around getting multiple PhDs would be akin to getting multiple bachelor degrees. People may see you as a permanent student, not someone growing into a mature researcher.

  • 2
    What do you mean by "same field"? For example, how about Mehanical engineering and aerospace engineering? or ME and EE? It is not clear to me how "same field" is defined. After all, most degrees in field of physics and engineering are based on same core equations and fundamentals (For example, in M.E. we use F=ma, and also the physics students use the same equation, does this mean one can't have a PhD in Physics and a PhD in engineering?). And who decides if the field is the same or not?
    – Nasser
    Jun 1, 2012 at 14:10
  • 4
    I think the answer is "it depends". Not me, that's for sure. Jun 1, 2012 at 15:09
  • 1
    @Nasser, I've never seen a case where it was cut so fine as different fields of engineering. I've seen a physicist move to philosophy, so obtained PhDs in both. The decision whether to allow enrolment in the second PhD seems to be a judgement call by the university where the criteria is that the research is sufficiently different that the candidate would, in a sense, be "starting again" - so their prior PhD is in theory no advantage. Again though, it's up to the institution. Of course no of this applies to higher or professional doctorates. Feb 22, 2013 at 3:30
  • 1
    @DaveClarke In the UK, you can get two PhDs in the same field (at least I see one case in Computer Science).
    – sean
    Jun 11, 2015 at 13:13
  • 2
    "obtaining a PhD is a small step along that career path": I'd have to disagree, actually, at least for certain cases. If you have a PhD in, say, sociology, and you obtain a PhD in statistics to support your research, that is by no means a small step. In fact, this would boost one's career quite a bit, even outside the original field.
    – Maxim.K
    Jul 14, 2016 at 14:26

I think it really depends on what the person actually wants to do with the two different degrees. For example if someone has both a PhD in chemisty and biology to become a biochemist, their understanding of the subject would be much more versatile. It is absolutely not nessesary by any means, but it would just depend on the person and how many angles they want to approach a subject; some people prefer more than one way of looking at something.


Most universities in the US prohibit awarding of duplicate or comparable degrees. For instance; one might have earned a PhD in Management from Papua New Guinea University, and planning to earn another PhD in Management from Yale. In this particular case, Yale won't admit that student. Similarly, HBS, NYU Stern, Berkeley Haas MBA program FAQ sections clearly state that they won't accept students who already hold an MBA degree from another institution.

"University policy prohibits awarding of duplicate degrees. If you have an MBA or comparable degree from an institute of higher education, your application will be ineligible for consideration."


  • 5
    This is, in fact, a general rule. American universities will not give degree X in field Y to someone who already has degree X in field Y. You already have an MBA? Then you can't get another MBA. You already have an MS in applied math? Then you can't get another MS in applied math. You already have a PhD in business admin? Then you can't get another PhD in business admin.
    – JeffE
    Feb 21, 2013 at 23:28
  • 6
    Not entirely true. I know of many people who got an MBA from the top management schools in India, discovered that the value of this degree isn't so great on the international scene, and did another MBA in the US or elsewhere. My cynical side thinks that an institution granting a professional degree merely wants your money in exchange for the certification, and doesn't care about your prior qualifications.
    – Suresh
    May 12, 2013 at 15:10
  • 2
    @Suresh If you referring to the IIMs, don't they technically grant a PGP degree and not a MBA per se (by a quirk of governmental bureaucracy) and are thus, able to get escape the no-MBA requirement? I like your cynicism (and share it) so +1. :D
    – Shion
    May 13, 2013 at 3:54
  • it's entirely possible.
    – Suresh
    May 13, 2013 at 4:15
  • 2
    Recently was I asked to check into the possibility of this in my department (mathematics, University of Georgia): is there a specific regulation against admitting a student into our PhD program who already held a doctoral degree in mathematics? The answer turned out to be no. (This is not to say that I endorse the practice or would necessarily have wanted to admit a student under such circumstances.) Jul 21, 2013 at 1:10

Most schools don't like duplicate degrees, especially ones in the United State. Schools in Africa or the UK usually allow it.

I know a Professor that had 5 doctorates (not honorary doctorates).

Professor Blight (PrEng) was an A-Rated researcher who held five doctoral degrees, and who was considered as one of the world’s leading thinkers in Geotechnical Engineering. He held BSc(Eng) and MSc(Eng) qualifications from Wits. He completed his PhD in Soil Mechanics and his DSc(Eng) in Geotechnical Engineering at London University, before returning to Wits. In 1985, he obtained his DSc(Eng) in Materials Engineering from Wits and another DSc(Eng) qualification from the University of Cape Town. In 2001, he obtained a D.Eng, degree from Wits focusing on the Application of Research in Practice.

With over 330 papers published in accredited journals, Professor Blight was internationally renowned as a researcher of the highest standing around the world. He was well published internationally and the author or co-author of several books.


In answer to this part of the question:

"Could a professor working in a university write up a thesis and submit it to his department to earn a second doctorate?"

Where that is allowed he would need to have been registered as a PhD student for the required period of time, which in many British institutions is three years if the research is full-time and longer if it isn't. Universities can't just dole out PhDs at the drop of a hat. The department and probably the higher degrees committee would also want to know in what framework he had carried out the research. I think he would have to do it outside of what he gets paid to do as a professor.

I am not sure how easy it would be to get round the requirement that a PhD student should have an appointed supervisor during those three years either. Of course he may not wish to do that, but if he did there might possibly be a way at some institutions.

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