The report by the Arab League Education, Science and Culture Organisation (ALESCO) said on Sunday that 70 million people older than 15 in Arab League member countries were illiterate.
It said that almost half of all women in the countries concerned - 46.5% - were unable to read or write, as against a rate of 25.1% among men.
The report noted that as a percentage of total populations, the number of illiterates had fallen over the past 35 years.
The overall rate had stood at 73% in 1970, but it was now down less than half of that proportion, to 35.6%, the report said.
In absolute numbers, however, there were 50 million illiterates in 1970, as against 70 million today. ALESCO, based in the Tunisian capital, Tunis, is part of the Arab League.