DNSO is the abbreviation for the Domain Name Supporting Organization, one of the three supporting organizations of the Internet Corporation for Assigned Names and Numbers (ICANN) called under the ICANN by-laws. It has now been succeeded by the Generic Names Supporting Organization (GNSO). The DNSO advised the ICANN Board about handling issues related to the Domain Name System (DNS). The DNSO was primarily established with an agenda about how and when to expand Internet by adding new top-level domain names other than the .com. 
The DNSO had two bodies known as the Names Council (NC), which mostly comprised of the elected representatives from the DNSO Constituencies and the other being the General Assembly (GA) comprising of the all interested entities and individuals. 
The initial constituencies of the DNSO were as follows:
- ccTLD Registries
- gTLD Registries
- Commercial and Business entities
- Non-Commercial Domain Name Holders
- Internet Service Providers (ISPs) and Connectivity Providers
- Registrars 
- The DNSO carries out the function of serving as an advisory to the ICANN Board and to provide the Board with substantive policies related to the Domain Name System.
- The recommendations provided to the Board by the DNS first need to build a consensus before submitting it to the ICANN Board.
- All the recommendations made by the DNSO to the Board are transferred to all the Supporting Organizations so that they can comment to the Board under the purview of their responsibilities.
The ICANN Board accepts the recommendations of the DNSO only if it thinks that:
- The policy is in the interest of the Corporation and helps to further the purposes of the Corporation
- The policy is in consistent with the Articles and Bylaws of the Corporation
- The policy was framed through an open and fair process
- The policy is not opposed by other Supporting Organizations
- The Board would not adopt any recommendation of the DNSO unless the votes are sufficient for adoption and are in favor of adoption by the Board excluding the votes of the DNSO-selected Directors.
- If the Board is not satisfied with a recommendation then it can return it to the DNSO for further consideration. It will cite the reasons for its declination of the recommendation. If the DNSO still doesn’t recommend an acceptable policy then the ICANN Board may initiate, modify or amend and then approve the recommendation. 
Current situation of the DNSO
The responsibilities of DNSO have now been undertaken by the Generic Names Supporting Organization (GNSO) of ICANN.  The DNSO has now been succeeded by the GNSO that relates to the generic top-level domain names. The ICANN by-laws have specified three supporting organizations to which the GNSO would belong. The main role of the Supporting Organizations (SOs) would be to encourage diverse and international participation in the arena of technical management of the Internet and to promote the development of Internet policy.