List of Social Democratic Party (Finland) breakaway parties
# List of Social Democratic Party (Finland) breakaway parties

Since the founding of Social Democratic Party of Finland in 1899 it has seen a steady number of splits and breakaway factions. Some of the breakaway organisations have thrived as independent parties, some have become defunct, while others have merged with the parent party or other political parties

| Year | Party | Leader | Status |
| - | - | - | - |
| 1918 | Communist Party of Finland | Yrjö Sirola | defunct |
| 1920 | Socialist Workers' Party of Finland | August Raatikainen | defunct |
| 1959 | Social Democratic Union of Workers and Smallholders | Emil Skog | defunct |
| 1973 | Socialist Workers Party | Pentti Waltzer | active |
| 1998 | Reform Group | Risto Kuisma | defunct |
