The 24-year-old forward failed to score in Russia, as Iran went out on the group stage, and he came under fire from supporters of his nation.
On Wednesday, Reza Ghoochannejhad had announced his retirement from Team Melli after six years.
Seen as the long-term successor to Iran great Ali Daei, Azmoun's retirement will come as a major blow to the Asian country, who have made steady progress under their Portuguese coach Carlos Queiroz.
"There are some things in life that will speak first to you. My mother had overcome a serious illness and I was happy, but unfortunately because of the unkindness of some people, and the insults that me and my team mates in no way deserved, her illness has become severe,” Azmoun said.
"This has put me in a difficult position where I must pick one or the other - and as a result I pick my mother," he concluded.