The London-listed company said on Monday that it landed $8 million from KRG for May exports.
"This is a partial payment of the invoiced amount and the balance is expected to be paid shortly," Gulf Keystone said.
Following the announcement, the company's shares were up around 6% on Monday morning in London.
Earlier this month, the Kurdistan-focused player received a final $7 million payment from the KRG for April exports, after previously receiving a partial payment of $6 million.