Counterclaim is one type of ancillary claims that has not been identified in the law of the administrative justice court and its filing in that court requires the hearing of the complaint by the government agency. According to the practical procedure of the administrative justice court, which that court does not have the jurisdiction to hear the claims of the government against the people, in the first place, it may be doubtful to file a counterclaim in the administrative justice court. Based on this, this research with a descriptive analytical method try to answer this question that according to the terms and conditions of filing a counterclaim, how is the possibility of filing this type of claim in the administrative justice court. Based on this investigations, it can be said that there are formal and substantive obstacles in front of filing a counterclaim in the administrative justice court, that the most important of them are: the administrative justice court not being recognized a court, the petitioner is not private, it is not possible to file an administrative claim by the government agency against the people, the lack of clarification of the law of the administrative justice court about counterclaims and being contrary to the principle, also the impossibility of compliance with the deadline and conditions such as unity of origin and communication. However, the findings of this research indicate the possibility of removing the above obstacles; Because according to the philosophy of identifying ancillary claims in the judicial system of the country and the benefits that can be identified for it, it is desirable to consider all types of ancillary claims, including counterclaims, in the administrative justice court and in this direction, it is better to provide an extensive and realistic interpretation of the formal and substantive jurisdiction of the administrative justice court.