Foreign postgraduate students on non-research courses will no longer be able to bring family members to the UK, under new immigration curbs.
The announcement has been made two days before official statistics are expected to show legal migration has hit a record 700,000 this year.
Last year, 135,788 visas were granted to dependants of foreign students, nearly nine times the 2019 figure.
PM Rishi Sunak told ministers the move would help bring migration down.
He told the cabinet that the change, to begin in January 2024, will make a "significant difference to the numbers," according to No 10.
Last week, he said ministers were "considering a range of options" to bring migration down, but refused to say what an acceptable level was.
The Conservatives have previously promised to bring net migration below 100,000 a year, but ditched the target ahead of the 2019 election after repeatedly failing to meet it.