HISTORY answers
Because Spain didnt need to get involve. Germany was actually giving Spain military equipment so thats why they stayed neutral.
Mainly due to the political instability and inconsistencies that happened to take place there in the early parts of the century. During WW2 they aligned themselves actually with the Germans During the cold.war spain wasnt nuetral. They were in NATO
Spain had no reason to fight in WW1 because it had no alliances with any of the nations that went to war. Spain was neutral in WW2 but friendly to Germany and Italy. The excuse used was that Spain was too badly damaged by the late civil war to fight again so soon. Spain did allow many 'volunteers' to fight on the Eastern Front against the USSR but not against any other Allied power. Spain was not neutral during the Cold War. Although not a NATO member until 1982, Spain had friendly relations and a bilateral alliance with the US, allowing US Air Force bases on their soil and regular visits from US warships. Spain's late joining was due to other NATO member states objecting to a formal treaty relationship with the undemocratic Franco regime. After the death of Franco, left wing political forces within Spain blocked NATO membership application for several years. - .--
http://countrystudies.us/spain/88.htm http://www.cvce.eu/content/publication/2010/4/28/831ba342-0a7c-4ead-b35f-80fd52b01de9/publishable_en.pdf
Prior to to World War one, many European nations had made pacts and alliance to prepared for war. However Spain was different, they made none. So when war did broke out, Spain had no requirements to join. So they didn't. Before WWII, Spain was caught up into a civil war. Once the Fascist force won the war in Spain. They stayed neuter. Spain only help the axis with Foreign volunteers.
Spain and Portugal were Not Neutral during WW2 they just said they were Portugal was selling Ore to the Nazis Spain was the Conduit for food Oil fuel supplied By standard Oil IG Farben up to July 1944 when France fell Spain was of Little Value to the Germans and the British in 1944 convinced the Portugal to stop dealing with the Nazis Sweden was selling Ball bearings to the German GM factory and also supplying the ITT Factory Ball bearings ITT was Building Focke Wulf's and we all Know that the Swiss who also claimed Neutrality wee Hitlers Bankers
Spain remained neutral throughout World War I between 28 July 1914 � 11 November 1918, but despite domestic economic difficulties,it was considered 'one of the most important neutral countries in Europe by 1915'. Spain had enjoyed neutrality during the political difficulties of pre-war Europe, and would continue its neutrality after the war until the Spanish Civil War began in 1936.While there was no direct military involvement in the war, German forces were interned in Spanish Guinea in late 1915, and Spain undertook efforts to aid prisoners of war during the conflict under Alfonso XIII, then King of Spain. Such efforts were matched by protests of Germany's U-boat use; Spain lost 140,000 tonnes of shipping to German submarines. The Spanish State under General Franco was officially non-belligerent during World War II. This status, although not recognised by international law, was intended to express the regime's sympathy and material support for the Axis Powers, to which Spain offered considerable material, economic, and military assistance. Despite this ideological sympathy, Spain did not enter the war as a belligerent and, in fact, frustrated German designs on Gibraltar and stationed field armies at the Pyrenees to dissuade Germany from occupying the Iberian Peninsula. This apparent contradiction can be explained by Franco's pragmatism and his determination to act principally in Spanish interests, in the face of Allied economic pressure, Axis military demands, and Spain's geographic isolation. (I'm not sure about the Cold War on the other hand)
Research
In world war 1...I don't know. But the Spanish civil war ended JUST before world war two started. Many considered it a dress rehearsal for ww2 because so many countries sent aid. Francisco Franco won out by the way, and Spain became fascist. It was in no position to fight in WW2. No one in Europe really fought in the cold war. They joined NATO, and weren't unfriedly, but werent as supportive as the UK, but wasn't as unfriendly as France(under Charles De Gaulle). So here in America, we don't care about Spain.
Spain is not a country.