The British government, through the Office of the British Prime Minister, Boris Johnson, said it would provide $100 million dollars (75.6 million pounds) to Ukraine through the World Bank.
The grants were aimed at keeping core state functions running and reducing financial stress caused by the Russian invasion.
Britain is seeking to play a central role in responding to Russia's invasion of Ukraine by providing defensive military assistance, arguing for tougher Kremlin sanctions and offering financial support.
However, the Johnson government has faced criticism that sanctions have been too slow and its refugee program has been underwhelming.
The latest cash round, which is in addition to the $290.95 million (220 million pounds) promised, could be used to pay public sector workers in Ukraine or fund pension and social security payments, British authorities said.
"While only Putin can completely end the suffering in Ukraine, today's new funding will continue to help those facing the deteriorating humanitarian situation," Johnson added.
The money will be disbursed through the World Bank's Multi-Donor Trust Fund, which is designed to accelerate donations to Ukraine and is already being used by several other countries.
The funding announcement comes ahead of a visit to London by Canadian Prime Minister Justin Trudeau and Dutch leader Mark Rutte, which Johnson will seek to use to strengthen the international response to the invasion.
The three leaders will hold a press conference on Monday.
