"The daily reality for many migrant workers in the country remains harsh, despite legal changes introduced since 2017," the London-based human rights group said.
It urged Qatar to abolish the so-called kafala sponsorship system which bonds foreign labourers to employers, making them more vulnerable to abuses such as late- and non-payment of wages.
"Apparent complacency by the authorities is leaving thousands of workers at continued risk of exploitation by unscrupulous employers, with many unable to change jobs and facing wage theft," said Mark Dummett, Amnesty's global issues program director.