Every member must be attached to a Parliamentary Group, which will necessarily be the corresponding party, group or electoral coalition during whose candidacy the elections were held, or were appropriate, a Mixed Group. The deputies belonging to the same political grouping or attending the autonomous elections in a given candidacy may not constitute a separate Parliamentary Group. The mininum number of members in order to constitute a parliamentary group is three. However, those deputies belonging to the same political grouping and having obtained at least 10 per cent of votes of the Region at the autonomous elections may constitute a Parliamentary Group, despite not meeting the requirement established in the previous paragraph.

Every Parliamentary Group has a Spokesperson, who is the deputy generally participating on behalf of his or her group and who holds its representation in the Board of Spokespersons. The judicial regime applicable to the parliamentary groups is gathered in section 29 of the Statute of Autonomy and developed in Part III (sections 27 to 38) of the Chamber Regulations.