According to Joseph Nye, who introduced the concept of soft power in the 1980s, soft power is a form of political influence that allows one to achieve the desired results based on voluntary participation, cultural cooperation, and the attractiveness of the country as a whole. This article examines the soft power policy of the United States of America and Russian Federation in Vietnam, examines the historical events of the 20th century, the Vietnam War, its consequences and the subsequent development of relations between the countries. The strengths and weaknesses of both countries are analyzed. The causes and consequences of the decline of Russian influence in Vietnam since the 21st century are revealed. As a result of the analysis, the author identifies the reasons for the low efficiency of Russian soft power in Vietnam, and the reasons for the high efficiency of US soft power. Author have analyzed such areas as (political, economic, cultural, etc.) in which the Russian Federation and the United States cooperate with Vietnam. In conclusion, the author draws conclusions about the effectiveness of the soft power of Russia and the United States in Vietnam, based on the analysis of bilateral relations between Russia-Vietnam and the United States-Vietnam.