As the Truman Doctrine and the Marshall Plan were formulated around the same time to meet interrelated challenges, they have many similarities. Ostensibly both policies sought to aid the countries of Western Europe. In his speech to Congress announcing the Truman Doctrine on March 12, 1947, President Truman described one the of the aims of his foreign policy as assisting "free peoples to work out their own destinies in their own way." The goals of the Marshall Plan also did confer many benefits on Western European nations. Infrastructure in war-torn Europe was repaired, food crises were alleviated, and industries in the recipient countries were modernized.

Beyond the benefits to Western European nations, however, both policies also served the interests of the United States in obvious and subtle ways. The Marshall Plan was drafted with an understanding of how the punitive peace terms that followed World War I and the economic devastation Europe experienced during the interwar years fostered the rise of extremist policies. Moreover, Hitler and the Nazis' power grew dramatically as the Great Depression set in. The Marshall Plan sought to avoid a repeat by helping Western European nations recover and get back to business. In this way, the Marshall Plan also served US economic interests by cultivating the prosperity of potential trading partners. The plan also fostered free trade between the nations of Europe, which allowed the formation of confederations like NATO and the EU.

NATO was a manifestation of the Truman Doctrine. It provided for the collective security of the nations of Europe but also helped American ensure its own. The Truman Doctrine was a policy of containment, designed not to overthrow the Soviet Union or oust the Soviets from the lands they had already taken but to prevent the spread of communism to new territories. Strengthening Western European countries through the Marshall Plan allowed these countries to resist communist overthrow. By helping them, we helped ourselves as these nations became the first line of defense in any potential war. In essence, spending money through the Marshall Plan allowed the US to avoid direct military confrontation in favor of the containment policies inspired by the Truman Doctrine.

One of the greatest differences between the two initiatives is that the Truman Doctrine was more overtly anti-communist. The Marshall Plan actually offered similar loans to the Soviet Union and Eastern Bloc territories. This showed that the plan was more concerned with preserving peace than confronting communism. The Soviets rejected the loans, however, because the terms required economic reforms antithetical to the very conception of state-planned economies.