The conceptual foundations of the United Kingdom’s economic diplomacy after Brexit is investigated in the paper. The role of economic diplomacy in supporting the country’s leadership and protecting national interests is analyzed. The program of economic diplomacy across five key areas: trade policy, shaping international norms and standards, concluding bilateral and multilateral agreements, participation in international organizations, and economic governance is systematized in the study. It is noted that the UK’s economic diplomacy system is based on a «whole-of-government» approach involving the Foreign, Commonwealth & Development Office and the De- partment for Business and Trade. This comprehensive strategy integrates efforts across external relations, domestic policy, commercial activity, and institutional development to consolidate the promotion of the United Kingdom’s national interests. The evolution of UK government agencies responsible for business, industry, and trade, leading to the establishment of the DBT in 2023 is examined in the research. The DBT’s key priorities, including economic growth, business support, promoting companies in global markets, fostering competition, advocating free trade, protecting business interests, supporting innovation, and leveraging post-Brexit opportunities are highlighted in the paper. It is distinguished that after Brexit, Britain seeks to diversify its trade ties by negotiating new bilateral free trade agreements and joining multilateral trade deals. It is noted that membership in the IMF, OECD, and G7 is crucial for the UK’s role in the global economy. Participation in shaping international norms and standards within organizations like the OECD and the World Customs Organization allowing Britain to play an active role in defining the «rules of the game» in global economic affairs and promoting its approaches in regulating trade, investment, and competition. It is concluded that economic diplomacy is a key instrument for advancing the UK’s trade, investment, and economic interests globally in the post-Brexit era.