What is the difference between a dissertation and a thesis?

The difference is mostly regional. In the United States a thesis is usually the document for a master's degree and a dissertation is for a PhD. In the United Kingdom and much of Europe it is reversed: a dissertation is often the master's document and a thesis is the PhD document. Both are long, structured pieces of original research; only the labels differ.

Do dissertations and theses have the same structure?

Broadly yes. Both typically follow a similar chaptered structure of introduction, literature review, methodology, results, and discussion or conclusion, scaled to the degree level. A PhD document is longer and demands a clearer original contribution, but the underlying architecture is the same.

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Dissertation vs thesis: what’s the difference?

Q: Is a thesis harder than a dissertation?

Not inherently; the difficulty depends on the degree level, not the word. A PhD-level document, whether your institution calls it a thesis or a dissertation, requires an original contribution to knowledge and is more demanding than a master's-level document. Always judge by the degree and your institution's requirements, not the term used.

Q: Which term should I use?

Use whichever your own institution uses, because their regulations define the term for your programme. When writing for an international audience, it can help to state the degree level explicitly (for example master's dissertation or doctoral thesis) so there is no ambiguity.

By Dr. Rafiq Muhammad, MD, PhD · Updated June 2026

This one confuses almost everyone, and for a good reason: the two words mean opposite things depending on where you are. The short answer — it’s mostly a regional naming convention, not a difference in the work itself. Both are long, structured pieces of original research; what matters is the degree level, not the label.

The US/UK flip

	United States	UK & much of Europe
Thesis	Master’s document	PhD document
Dissertation	PhD document	Master’s document

So an American “dissertation” and a British “thesis” can refer to the same thing — the big doctoral document — while the other term means the master’s one. No wonder the search results contradict each other.

Is one harder than the other?

Not because of the word. Difficulty tracks the degree level, not the label: a doctoral document — thesis or dissertation, whatever your institution calls it — requires an original contribution to knowledge and is more demanding than a master’s-level one. Judge the scale of the task by the degree and your institution’s regulations, never by which of these two words appears on the cover.

Which term should you use?

Use whatever your own institution uses — their regulations define the term for your programme, full stop. When writing for an international audience, you can sidestep the ambiguity by naming the level explicitly: “master’s dissertation” or “doctoral thesis.” Either way, the structure is broadly the same — introduction, literature review, methodology, results, discussion — scaled to the level.

Whichever word your university uses, the document is built the same way. See the dissertation structure guide for the standard chapters and what each one has to do.

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Frequently asked questions

Dissertation vs thesis — the difference?

Mostly regional. US: thesis = master’s, dissertation = PhD. UK/Europe: reversed. The work is similar; the labels differ.

Is a thesis harder than a dissertation?

Not inherently — difficulty tracks the degree level (PhD vs master’s), not the word.

Which term should I use?

Whatever your institution uses. For international readers, state the level (master’s dissertation / doctoral thesis).

Same structure?

Broadly yes — introduction, literature review, methodology, results, discussion — scaled to the degree.

Dissertation structure → Open the Dissertation Timeline Planner →