They never did. They are neutral.
They did join in. In World War 2 only Sweden, Switzerland, Spain, Portugal and Ireland remained neutral.
Switzerland maintained strict neutrality during both wars
It's Switzerland. They're always neutral.
Switzerland
Switzerland, and Netherlands were neutral during world war 2
Switzerland was Neutral during WWII
Switzerland has always been known as Switzerland.
Switzerland
Switzerland
Switzerland
no
Switzerland did not take part in WW2. It was neutral.