This essay provides a comparative analysis of the monetary and fiscal policies implemented by the UK and the US in response to economic challenges, particularly during the COVID-19 pandemic. Utilizing the Keynesian economic theory, it examines how both countries employed different strategies to stabilize their economies, support employment, and ensure the smooth flow of credit. The essay discusses specific measures taken by the Bank of England and the Federal Reserve, including interest rate adjustments, asset purchases, and fiscal stimulus packages. It highlights the impact of these policies on GDP, employment rates, and overall economic stability in both nations, concluding that while approaches varied, both countries demonstrated significant efforts to mitigate economic downturn and foster recovery.