You can search for Oxford MPhil and DPhil archaeology theses on SOLO. Simply search for "oxford thesis archaeology" plus any keywords if you are interested in a particular subject.
DPhil theses can be requested on SOLO from the Bodleian Bookstack to the Weston Library for consultation.
Some recent dissertations may be available online on ORA (Oxford Research Archive) These will also be listed on SOLO.
Dissertations, portfolios and theses written by Continuing Education Archaeology students are available for consultation in the Rewley House Continuing Education Library . Recent years are shelved under the stairs in the Lower Library, ask staff for older titles. A list of titles held is available in the Library.
EThOS lists British doctoral theses, providing online access to many of them.
Worldwide Dissertations and Theses
Dissertations and Theses contains details of theses from around the world dating back to 1637, many of which are available in full text.
For more information about finding theses, see the Bodleian Libraries website.