Socialist Democratic Party
Socialist Democratic Party may refer to:
- Kurdistan Socialist Democratic Party
 - Lithuanian Popular Socialist Democratic Party
 - Mongolian New Socialist Democratic Party
 - Russian Socialist Democratic Party
 - Socialist Democratic Party (Canada)
 - Socialist Democratic Party (Chile)
 - Socialist Democratic Party (Japan)
 - Socialist Democratic Party (Turkey)
 - Socialist Democratic Party (India)
 - Social Democratic Party of Germany
 - Social Democratic Party in the GDR
 - Social Democratic Party (Bosnia and Herzegovina)
 - Social Democratic Party (Croatia)