EATA (European Association of Transnational Analysis)

Governing body for Transactional Analysis in Europe.

ITAA (International Transactional Analysis Association)

Governing body for Transactional Analysis outside of Europe. 

T&CC (Training & Certification Council of Transactional Analysis)

Information about training and certification (CTA and TSTA) and contacts for TA associations worldwide, as well as exam dates.

UKATA (UK Association for Transactional Analysis)

Governing body for psychotherapy and counselling Transactional Analysis in the United Kingdom.

ITDA (Institute of Developmental Transactional Analysis)

UK body promoting the Organisational and Educational aspects of Transactional Analysis.

IARTA (International Association of Relational Transactional Analysis)

Promotes the use and investigation of the Relational tradition within Transactional Analysis.

USATAA (United States of America Transnational Analysis Association)

Association of practicing TA professionals in USA.

NZTAA (New Zealand Transactional Analysis Association)

Association for New Zealand

SATAA (South African Transactional Analysis Association)

Association for South Africa

SAATA (South Asian Association of Transactional Analysis)

Association for South Asia

STAA (Scottish Transactional Analysis Association)

Association for Scotland

Note that many other countries have their own TA associations in their own language. These are the main ones affecting the UK and English speaking world. For a fuller list, see the ITAA's TA Community page.