Thesis vs dissertation: what the terms mean in the US, the UK, and beyond

The two words swap places depending on the country. A student in Ohio writes a master's thesis and a doctoral dissertation. A student in Manchester writes a doctoral thesis and, on a taught master's, a dissertation. Both are correct where they are written, and both can confuse a supervisor, a journal editor, or an online guide written for the other country.

This guide sets out how the words are used in the main systems, so you can tell which one applies to you.

The United States

In the US, the dissertation is the book-length study that ends a doctorate: a PhD, EdD, DBA, or similar. The thesis is the longer paper that some master's programs require, and many master's programs offer it as an option beside coursework or an exam.

Our guides to the chapters of a dissertation follow this usage, which is why they refer to committees, proposals, and IRB approval. Most of what they say about structure carries over to other countries, even where the labels differ.

The United Kingdom and Ireland

The labels reverse. A doctoral thesis is the document you defend in a viva. The word dissertation is kept for shorter research projects, usually the final piece of a taught master's degree or a bachelor's degree with honours.

A research master's, such as an MPhil or MRes, is normally written up as a thesis. If your program calls the project a dissertation, it is smaller, and your supervisor is likely to mark it and not send it to an external examiner.

Canada, Australia, and New Zealand

Canadian universities usually call both the master's and the doctoral document a thesis, though some use dissertation for the doctorate. Australian and New Zealand universities use thesis for research degrees at both levels, and dissertation for a smaller project in a coursework master's.

Examination differs from the US as well. In Australia, a doctoral thesis is usually sent to external examiners who write reports on it, and many universities hold no oral defense. Canadian programs normally hold an oral defense. Check your own regulations for the format that applies to you.

South Africa and Kenya

Many South African universities call a master's research report a dissertation and a doctoral document a thesis, which matches the UK. Kenyan universities vary. A PhD document is a thesis. A master's by research may be called either, and a coursework master's project is often a project report or a dissertation. Some universities in both countries hold an oral examination for the doctorate, called a viva or viva voce, and others examine the written document alone.

Europe, the Gulf, and Asia

European systems follow the Bologna degree structure, but the doctoral defense differs by country, and our guide to thesis defense in Europe covers four of them. Gulf universities add an Arabic abstract and set their own citation style, which our guide to the Gulf states explains. For India, China, Singapore, and Malaysia, see our guide to Asia. The labels thesis and dissertation follow your university's regulations in each of them.

Why the word matters

The label affects practical things, and these are worth checking at the beginning of the project.

• The regulations. Word limits, structure, examination format, and approval steps are attached to your degree, not to the word you use for it. Read your university's research degree regulations first.
• Searching for help. A guide written for a US dissertation may call something a committee that your university calls a supervisory panel. The advice usually applies, but the names of the steps change.
• Citing and submitting. Repositories and library catalogs ask for the document type. Use the label on your degree certificate's regulations, not the one you prefer.
• Talking to examiners. In a viva, a supervisor who says "your dissertation" about a doctoral thesis is simply using the other word. Do not correct them.

What stays the same

The research problem, the question, the literature review, the method, the findings, and the argument that holds them together are the same in every system. A weak chapter alignment gets flagged by a US committee and by a UK external examiner for the same reason. Our guides to Chapter 1, Chapter 3, and Chapter 4 apply wherever you write.

If you are preparing for an oral examination, read our guide to the PhD viva. If you work outside the US and need ethics approval, see ethics approval outside the US. If your university asks for Harvard referencing, see our Harvard referencing guide.

We work with master's and doctoral researchers in several countries. If your manuscript needs a review before submission, our editing and formatting service works to your university's own requirements.