Ottmar Schreiner (21 February 1946 – 6 April 2013) was a German lawyer and left-wing politician.

In the election for federal Juso chairmanship in 1977, he was defeated by Klaus Uwe Benneter, who was later suspended from the SPD, and in 1978 he lost to Gerhard Schröder.

He received a direct mandate in the electoral district Saarlouis, which he defended at the federal elections in 2005.

From 1991 to 1997 he was a speaker of the SPD's parliamentary group in the Ausschuss für Arbeit und Sozialordnung (Committee on work and social order).

He was the chairman of the Arbeitsgemeinschaft für Arbeitnehmerfragen, a study group inside the SPD, which is reputed to be leftist and closely connected to trade unions.