The bodies for the preparation of the decisions of the Plenary meetings, although they replace the latter when acting with full normative powers. They are made up of the members appointed by the Groups of Representatives in the numbers allocated by the Board of the General Assemblies, in consultation with the Board of Spokespersons, and based on the numerical weight of each of the groups in the Chamber. Each Group of Representatives shall be entitled to at least one member in each and every ordinary Committee created. The ordinary Committees shall make decisions using the majority system, and in case of a tie, the weighted voting system shall be used based on the numerical weight of each group in the General Assemblies. The Groups of Representatives may freely replace their members.

The General Assemblies Committees may be ordinary or special. The former are compulsory under the Chamber's Regulations. The latter are set up for a specific activity and then dissolved at the conclusion of the activity and in any event at the end of each term of office of the General Assemblies. It is the responsibility of the Board of the General Assemblies to approve the rules for the constitution, organisation and operation of the committees.

With the exception of the Regulation and Governance Committee, all other Commissions elect a Board from among their members, made up of a President, a Vice President and a Secretary.