The German Socialist Labour Party of Poland (German: Deutsche Sozialistische Arbeitspartei Polens, abbreviated DSAP, Polish: Niemiecka Socjalistyczna Partia Pracy w Polsce) was a political party organizing German Social Democrats in interbellum Poland.

Nominally, the DSAP was founded at a conference in Chorzw on August 9, 1925, through the merger of the Silesia/West Prussia-based German Social Democratic Party of Poland (DSPP) and the d-based German Labour Party of Poland (DAP). The merger wasn't fully effective though, and in practice the two parties continued separate existences until the merger was finalized until 1929.An 'Executive of the DSAP' was formed after the nominal founding of the party, consisting of Siegmund Glcksmann, Johann Kowoll, Buchwald, Kociolek, Ludwig Kuk, Klim, Arthur Pankrantz and Emil Zerbe. Kattowitzer Volkswille was assigned as the central party organ. One of the first actions of the party executive was the publication of the 'Manifesto of the united 'DSAP.

DSAP became the second largest party in the 1927 Lodz city council election, trailing behind the Polish Socialist Party (PPS). DSAP got 16,643 votes and seven seats in the council. In central Poland the municipal elections showed the strength of the party in the region; in total DSAP had 36 city councilors and 7 magistrate members in the area. In 1928 the party claimed to have 8,406 members, out of whom 2,500 were women. The youth wing of the party had around 1,200 members, out of whom 480 were women. The party had an educational organization, Bund fr Arbeiterbildung (6,000 members) and a children's organization, Kinderfreudegruppen (300 members).In June 1928 the Bydgoszcz branch of the party had broken away, forming a separate German Social Democratic Party of Poland.In Silesia, the situation was somewhat different from in central Poland. In Upper Silesia, the party did not fare too well in municipal polls. In the 1929 city council election in Katowice, the party mustered to get two seats. In Bielsko, the result was better for the party in local elections. In the 1929 city council election the party won eight seats (in alliance with the PPS).On October 67, 1929, a conference was held in Lodz which completed the task of unification of the DSAP set up at Chorzw four years earlier. The conference finally decided to locate the DSAP headquarters to Lodz (an issue that had been a bone of contention for years). Lodzer Volkszeitung was declared as the central party organ. Several representatives of the Labour and Socialist International and socialist parties participated as guests to the Lodz conference, including the SPD leader Johannes Stelling, the PPS chairman Herman Diamand, the leader of the Jewish Bund Henryk Ehrlich.In October 1930, DSAP suffered another split, as the leftist Heinrich Scheibler broke away and formed the German Socialist Labour Party in Poland Left (DSAP-Linke). Scheibler was able to take parts of the party organization in the d area with him.DSAP was fiercely opposed to the pro-National Socialist Young German Party (JdP), which had its base in Bielsko. The rise in popularity of National Socialism amongst the Germans in Poland would prove disastrous for the DSAP. In Upper Silesia, support for the party rapidly eroded after the 1933 Machtbernahme.

In SeptemberOctober 1933 DSAP joined the call initiated by the Bund for boycott of goods from Germany, in protest of the Hitler regime. The boycott call became controversial within DSAP, and some members (such as

Arthur Kronig, Otto Heike, Ludwig Kuk and Gustav Ewald) left the party as a result.

In 1932 the DSAP had 5,429 members in Upper Silesia. By 1937 the number had declined to 560. As of early 1936, the party had only three functioning branches in Upper Silesia, Katowice, Chorzw and Bielszowice. The Bielszowice branch went defunct before the end of the year, though. By March 1937, the remainder of the DSAP branch in Chorzw joined the PPS.On August 26, 1939, DSAP signed the joint statement of socialist parties in Poland, calling for the people to fight against Hitlerism (other signatories included the Bund).The party was a member of the Labour and Socialist International between 1923 and 1940.

The German Socialist Labour Party in Poland – Left (German: Deutsche Sozialistische Arbeitspartei in Polen – Linke, DSAP–Linke; Polish: Niemiecka Socjalistyczna Partia Robotnicza w Polsce – Lewica) was a political party in the Second Polish Republic. The party was founded on October 3, 1930, as a leftist split from the German Socialist Labour Party of Poland (DSAP) in Łódź.Most of the members of the North Łódź party branch of DSAP (German: Ortsgruppe Lodz-Nord) joined DSAP–Linke in the split. The DSAP–Linke also attracted some recruits from Ortsgruppe Lodz-Chojny of the erstwhile DSAP. Some other DSAP–Linke members were recruited amongst German and Jewish workers in Stryków, Brzeziny and Tomaszów. However, the total membership of DSAP–Linke didn't exceed 200.DSAP–Linke was led by Heinrich Scheibler, who had been the chairman of the Lodz-Nord party branch of DSAP and who in 1930 had become member of the DSAP Party Council. Schlieber had advocated that DSAP should seek cooperation with other leftwing parties, for unity between socialists and communists in struggle against reaction. Other founding members of DSAP–Linke were Johann Rückert, Oskar Fiebig, Adolf Jedich, and Joseph Dillner.After the split, the relations between DSAP–Linke and the mother-party DSAP (or DSAP–Rechts, i.e. 'DSAP–Right', as DSAP–Linke branded the party) were antagonistic. DSAP–Linke characterized DSAP and the Polish Socialist Party (PPS) as 'social fascists', arguing that the leaderships of those two parties were laying the foundations for fascism in Poland. The DSAP press organs, on their behalf, began using the spelling 'Szajbel' for Scheibler's name, thus insinuating that he was Jewish (Scheibler had married a Jewish woman).The peak of activity of DSAP–Linke coincided with the 1930 October–November campaign ahead of the parliamentary election. DSAP–Linke contested the election in coalition with the Polish Socialist Party – Left, running on joint lists titled PPS–Lewica (List 23). The bloc propagated the formation of a Workers-Peasants government and self-rule for national minorities, political stands that attracted sharp attacks from the Sanacja government and the Centrolew opposition coalition (in which the DSAP participated). The Polish government classified the DSAP–Linke as 'crypto-communist'. The list on which Scheibler was the number 2 candidate was declared invalid by the Polish government.On January 5, 1931 DSAP–Linke organized an assembly in Łódź. The political police, assisted by uniformed policemen, arrested all participants and party materials were seized. 46 participants were accused of anti-state activities. In October 1931, a legal case against twenty-two party cadres accused of connections with the Soviet Union, was opened. Scheibler was threatened with two years imprisonment, but on March 23, 1932 he was found 'not guilty'.After a short existence, DSAP–Linke became defunct. Already after the 1930 election, the view inside the party was that the party was lacking prospects for the future. Sometime around 1932 Scheibler joined the Communist Party of Poland (KPP). Most members of the political activist core of DSAP–Linke also joined KPP. Some former DSAP–Linke members rejoined DSAP.