Victor Adler (June 24, 1852, Prague – November 11, 1918) was an Austrian Social Democratic leader.

Born in Prague, Adler received a university degree in Vienna in 1881. He founded the Socialist movement in Austria and created the Marxist journals Gleicheit (Equality) in 1886 and Arbeiter-Zeitung (Workers' Paper) in 1889. That year he participated in the Hainfelder Parteitag, the conference which took part in Hainfeld to form the Social Democratic Party of Austria. As a member of the provincial parliament (from 1905) he played a leading role in the fight for universal suffrage.

Before World War I, Adler was a moderate social democrat and leader of the Socialist Party in Vienna. He publicly backed the Imperial government's decision to go to war, but had private misgivings. He was the father of Friedrich Adler. He died in Vienna.