"Today we have decided to resign from the GTA. The resignations will be submitted to the principal secretary of GTA," GJM general secretary Roshan Giri told PTI.
The GJM supremo Bimal Gurung, who is in hiding, will also put in his papers.
He said the GTA has been turned into a "farce" by the West Bengal government and the GJM and the people of the hills will fight for the single agenda of a separate Gorkhaland.
In the June 20 meeting all the 14 influential political parties and public organisations of the hills had unanimously declared their support to the longstanding demand for a separate Gorkhaland state in north Bengal.
The GJM is spearheading the agitation for a separate state and its indefinite shutdown, which has paralysed hit the normal life in the hills, entered its eighth day today.
The GJM has been ruling GTA since 2012 and its five-year term is set to expire this year.