The Christian Social Party (CSP) (German: Christlich-soziale Partei, French: Parti chrétien-social) is a political party in Switzerland of the Christian left. The CSP is more aligned with social democracy than the other major Christian party, the Christian Democratic People's Party of Switzerland (CVP), which is more economically liberal. With the moderate Christian left as its background, the CSP commits itself to social-democratic and environmentalist political solutions. The core principles of the CSP contain, among others, "solidarity with the socially and economically disadvantaged and the preservation of the environment."
As of 2016, the CSP does not hold any seats in the National Council of Switzerland.
A seat in the lower house was once held for decades by Hugo Fasel representing the canton of Fribourg.
On a cantonal level, the CSP has many elected members, mainly in the Roman Catholic cantons of Valais, Fribourg, Obwalden and Jura. In the latter, the CSP had until late 2010 one elected member in the Executive body, the Conseil d'Etat of the Republic of Jura.
The CSP is a centre-left political party and has strong environmentalist views. It also has social values and aims for taxing richer people. On a societal point of view, it has very liberal views and acts in favour of abortion rights, same-sex relationships and euthanasia, which differs strongly with other common Christian political parties, which traditionally are socially conservative.