•
In Defense of Animals, a non-profit organization for animal rights activism •
Indian Dental Association •
IDA Ireland, formerly the Industrial Development Authority •
Infocomm Development Authority of Singapore, a statutory board of the Singapore government •
Information Design Association • or Danish Society of Engineers, an association for engineers and others in technology •
Institute for Defense Analyses, a U.S. non-profit corporation that administers three federally funded research and development centers •
International Dark-Sky Association, a U.S.-based non-profit organization •
International Depositary Authority, established by the Budapest Treaty for the deposit the biological material for the recognition of patents, such as the
Microbial Culture Collection •
International Desalination Association, a global organization dedicated to desalination, desalination technology and water reuse •
International Development Association of the World Bank Group •
International Disability Alliance, an international alliance of individuals to defend the rights of those with disabilities •
International Dispensary Association Foundation a NGO dedicated to improving access to medications in the developing world •
International Documentary Association, a non-profit organization promoting documentary film, video and new media •
International Dyslexia Association, a non-profit education and advocacy organization •
Investment Dealers Association of Canada, now part of the Investment Industry Regulatory Organization of Canada •
Islamic Democratic Alliance, aka Islami Jamhuri Ittihad, a defunct Pakistani electoral alliance •
Issues Deliberation Australia/America, a public policy think tank based in South Australia and Texas ==Places==