Tsipras, of the leftist Syriza party, was elected only in January, based on his opposition to stringent austerity measures.
In last Friday’s vote that approved the most recent bailout, the Prime Minister effectively lost his parliamentary majority. He faced a rebellion by Syriza party members, where some 43 MPs either opposed or abstained, denouncing the attached austerity conditions.
The bailout allowed Greece to repay a substantial debt to the European Central Bank and avoid a default, but had to agree to severe sector cuts, which will include extensive pension reforms.
According to Tsipras, conditions had to be accepted for Greece to retain its place in the Eurozone.
In a televised state address on Thursday, Tsipras announced his resignation and called for elections, which he described as his moral duty.
“The political mandate of the 25 January elections has exhausted its limits and now the Greek people have to have their say,” said the Prime Minister.