Infantino, who is seeking reelection next year, has faced open revolt after three confederations - UEFA, AFC and CONCACAF - called for him to quit over his aborted bid to bring private investment into FIFA competitions, including the World Cup.
The Swiss administrator had proposed carving off the commercial rights to the World Cup and selling 20% to private investors to raise about $4.2 billion.
"Recognising the important role of Arab football in bringing people together and strengthening cooperation among football associations across the Arab world, we ... express our full support for Mr Gianni Infantino, president of FIFA, and reaffirm our confidence in his leadership and continued commitment to the development of football worldwide," the heads of the six federations said in a joint statement.
The statement was signed by the heads of the national federations of Qatar, Lebanon, Morocco, Sudan, Egypt and Mauritania. Four of the six signatories are also FIFA Council members.
"We deeply appreciate Mr Infantino’s sustained efforts to advance football globally, expand opportunities across all regions and strengthen the game’s role in bringing people and communities together," they said.
"We look forward to continuing our close cooperation with him towards a stronger and more prosperous future for world football, expanding opportunities and further enhancing Arab football’s contribution to the global game."
Infantino’s withdrawn proposal came with a $20 million grant for member associations for the next funding cycle, an amount that could have been doubled if they signed the deal.
Despite the opposition of the three confederations, which represent 136 of the 211 member associations who will vote in the FIFA presidential election in March, Infantino still has plenty of allies in the game.