In embodiments of mesh network commissioning, a border router receives a petition from a commissioning device to become the commissioner for a mesh network, and commission joining devices to join the mesh network. The border router transmits the received petition to a leader device of the mesh network, and receives a response to the petition from the leader device, where the response indicates acceptance or rejection of the petition. In response to receiving the response to the petition from the leader device, the border router transmits an indication of the acceptance or the rejection of the petition to the commissioning device. An acceptance of the petition by the leader device authorizes the commissioning device to be the commissioner for the mesh network and a secure commissioning session is established.