The seven were sentenced to death in 2009 for an armed robbery in 2006, but Amnesty quoted the men as saying they were tortured into confessions. It said King Abdullah ratified their sentences in February, Reuters reported.
"They have since said they were severely beaten, denied food and water, deprived of sleep, forced to remain standing for 24 hours and then forced to sign 'confessions'," said Amnesty.
A spokesman for the kingdom's Interior Ministry was not immediately able to comment on the report, but has repeatedly said in the past that Saudi Arabia does not practice torture.
The last time the kingdom executed so many people at once was in October 2011, when eight Bangladeshi men were put to death for an armed robbery in which a guard was killed.
The seven are from the Southern province of Asir, one of the least developed in the kingdom, the world's top oil exporter.
Saudi Arabia has executed 17 people so far this year, said Amnesty, compared to 82 in 2011 and a similar number last year.
Capital crimes resulting in the death sentence last year included murder, armed robbery, drug smuggling, sorcery and witchcraft.
In January, United Nations Secretary General Ban Ki-moon expressed dismay at the beheading of a Sri Lankan maid convicted of murdering a baby.
The UN Office of the High Commissioner for Human Rights said in a 2006 report that it was "deeply alarmed" at the imposition of capital punishment by Saudi judges for crimes committed before the age of 18.
