Morgnshtern (מאָרגןשטערן, Yiddish for 'Morning Star', sometimes also known by its Polish name Jutrznia) was a Jewish sports organisation in interbellum Poland, politically linked to the Bund. It was founded in the end of 1926. Morgnshtern increased significantly in influence in the period just preceding the Second World War. In 1937 the organisation had 107 local branches in different parts of the country. Its largest branch was based in Warsaw. In 1936, the Warsaw branch had 956 active members, in 1937 he membership reached around 1500 (making it the largest local sporting organisation in Poland) and 1855 in 1938.
Morgnshtern was repeatedly targeted by the Polish authorities; between 1929 and 1934, 23 local Morgnshtern branches were closed down. In 1937 Morgnshtern had prepared a delegation to take part in the Workers Olympics in Antwerp, Belgium, but the Polish government refused to give travel visas to the athletes.
The development of socialist sports was markedly affected by the rise of fascism in Europe. The socialist sport movement took a more paramilitary character, in order to mobilize anti-fascist defense. In the case of Morgnshtern, the Bund already had experiences from organizing militias against pogroms. Bernand Goldstein, the president of the Morgnshtern in Warsaw was also the chief of the Bundist Defense Corps (Goldstein himself did however later downplay his role in Morgnshtern, stating that the presidency was merely an honorary position).
Morgnshtern ceased to function as Poland was occupied by Germany. Many of the athletes of the organisation became resistance fighters during the war.Morgnshtern was revived after the war. Warsaw "Jutrznia-Morgnshtern" is the only remaining Morgnshtern branch.
Morgnshtern espoused principles of socialist sporting, seeking to promote proletarian camaraderie and collective achievements, rather than individual competition. These principles had been formulated in the book Sport und Politik ('Sports and Politics') by Julius Deutsch. Initially the organisation mainly organised sports were large numbers of people could participate at the same time, such as cycling, gymnastics and hiking.