International

• Networked Digital Library of Theses and Dissertations (NDLTD)
  An international organization dedicated to promoting the adoption, creation, use, dissemination and preservation of electronic analogues to the traditional paper-based theses and dissertations.

Spain

• Bases de datos de tesis doctorales (TESEO)
  TESEO compiles and provides information on doctoral theses from Spanish universities since 1976.
• Catálogo de tesis doctorales catalanas
  Electronic catalog of doctoral theses from Catalonia.
• Portal de tesis digitales de REBIUN (Red de Bibliotecas Universitarias)
  Provides access to theses in digital format.
• Tesis doctorales—via Biblioteca Virtual Miguel de Cervantes
  Provides an electronic catalog of theses from Spanish universities. Arranged alphabetically by university. Some full-text available.

Portugal

• Dissertações e Teses Digitais (DiTeD)
  Theses and dissertations from Portugal deposited at the Biblioteca Nacional in Lisbon and made available in digital format.
• Teses Portuguesas sobre Temas Europeus
  Portuguese theses on European subjects.
• Teses sobre temas relacionados com História da Ciência, realizadas em Universidades Portuguesas, desde 1990
  Theses about the history of science defended in Portuguese universities since 1990.