Spain's contribution to the Allies was largely in the form of the Blue Division, a unit or Spanish Volunteers that served on the Eastern Front. However, Spain did make it evident that it wasn't interested in aiding the Axis militarily or officially when Franco pulled the Blue Division and all other Spanish advisers and troops back to Spain, and then refused to officially enter the war on the side of the Axis. He also significantly rejected Operation Felix, a proposed German plan to seize the British territory of Gibraltar. Franco simply believed that Spain was too weak after its Civil War and could not wage a war unless tremendous amounts of food and material was provided by the Axis powers to feed and maintain any Spanish forces that would be contributed. This helps put the state of the Spanish economy a bit into perception.

The amount of financial, economic, or resource aid that Spain gave to the Axis wasn't enough to make the Allies consider a war with Spain. Spain did not really provide any of those anyways, and if it did, it would have been in very, very low amounts. It's only contribution was the Volunteer divisions, which Franco explicitly stressed could and would only be allowed to be used to fight against Communists on the Eastern Front. Spanish Volunteers weren't exactly that numerous either, and there was no need to go to war over the issue either when the Allies were able to simply diplomatically pressure Franco into withdrawing any and all troops helping the Axis on the Eastern Front. They negotiated with him in the spring of 1943, and Franco began to pull out Spanish troops by October 10th of the same year, ending any sort of Spanish involvement in the Second World War.

The fact that Spain helped the Axis wasn't seen as a reason to "punish" or attack Spain anymore than Sweden selling lots and lots of Iron Ore to Germany throughout WW2 made the Allies want to "punish" or invade Sweden. There was no real reason to declare war on Spain unless Spain became an aggressor herself. Most importantly, Spain was rabidly anti-communist, and in the 1950's, Spain was a prominent anti-communist country, with Franco himself being one of the world's most important anticommunist figures. Combined with the fact that Franco's regime gradually became less extreme and less of a dictatorship, the United States became a close ally of Spain and Franco in the 1950's as part of the containment policy of America. Spain fell into an agreement with the States in 1953 with the signing of the Pact of Madrid, and joined the United Nations in 1955.