This chapter looks at the cooperation and competition between Chinese, British, and American actors in the context of the changing situation and the decline of British influence in South China during the war. The many military formations and organizations of the three powers, often with limited resources because of their relative perceived importance in their countries’ overall planning, competed for influence in the area while waging war against Japan. While the Americans enjoyed clear superiority in materials and resources, the British in South China relied on preexisting networks and local knowledge. The Chinese Nationalists and Communists, on the other hand, interacted with the British and Americans to advance their positions. In all, despite competition, the Allied forces in South China did operate effectively against Japan, especially in terms of sustaining an air campaign against Japanese logistics and infrastructure in the area, although such cooperation was strained to limits in 1944–1945. The war eventually led to a collapse of British influence in South China and the emergence of increased Sino-American ties.