Charles Eustis "Chip" Bohlen (August 30, 1904–December 31, 1974 ¹), was a United States diplomat (1929–1969) and Soviet Union expert, serving in Moscow before and during World War II, succeeding George F. Kennan as US Ambassador to the Soviet Union (1953–1957), then moving to the Philippines (1957–1959), and to France (1962–1968).

Bohlen early on warned against overly optimistic views in the West about the Soviet Union's intentions after World War II, arguing that the Kremlin rulers were paranoid and despotic and could not be trusted. His view was only slowly gaining followers in the State Department, but eventually his assessments would prevail in the policy of containment during the Cold War.

In his memoirs, Witness to History (1973), he reveals that on the morning of August 24, 1939, he visited the Third Reich diplomat Hans von Herwarth and received the full content of the secret protocol to the Molotov-Ribbentrop Pact, signed the day before. The secret protocol contained an understanding between Adolf Hitler and Joseph Stalin to split Central Europe, the Baltic region, and Finland between their nations. US President Franklin D. Roosevelt was urgently informed. The United States did not conduct this information to any of the concerned governments in Europe. A week later the plan was realized with the German invasion of Poland, and World War II was commenced.