James Hudson Maurer (April 15, 1864 – March 16, 1944) was a prominent American socialist politician and trade unionist who twice ran for the office of vice president of the United States on the ticket of the Socialist Party of America. He served three non-consecutive terms in the Pennsylvania House of Representatives between 1911 and 1919, and as President of the Pennsylvania Federation of Labor from 1912 to 1928.

Maurer was born in Reading, Pennsylvania, on April 15, 1864, and was one of three brothers. His father, James D. Maurer, was a shoemaker who later served as a Police officer in Reading. Maurer first went to work at the age of 6 as a newsboy, becoming an assistant to a plumber at the age of 10, later becoming a full-fledged plumber. The Maurers were of Pennsylvania Dutch ethnic extraction and the family had ancestors in America dating back nearly two centuries.

Maurer joined the Knights of Labor labor union on his 16th birthday in April 1880. He was also active in the Single Tax movement associated with Henry George. In the early 1890s, he joined the People's Party, a populist political organization which attempted in particular to advance the cause of the country's farmers. He was introduced to socialist ideas near the end of the decade, taking nearly a year to read Karl Marx's Capital before joining the Socialist Labor Party of America (SLP) in 1899. Maurer helped to organize Section Hamburg, Pennsylvania SLP, in February of that year.

From 1901, Maurer was a member of the Plumbers and Steamfitters Union. Throughout his later life, he was strongly supportive of the American Federation of Labor and he came to strongly disapprove of the SLP's efforts to establish a competing socialist trade union to the AF of L, the Socialist Trade and Labor Alliance, and left the SLP to join the Socialist Party of America (SPA) in 1901 over this issue. He ran for governor of Pennsylvania on the Socialist Party ticket in 1906, receiving nearly 26,000 votes.

In November 1910, Maurer was elected as a Socialist to the Pennsylvania House of Representatives, serving during 1912. During his term in the legislature, Maurer fought for the passage of a plan for Old Age Pensions and attempted to prevent the establishment of a State Constabulary, which was seen as a mechanism for the armed and organized breaking of strikes.

Also in 1912, Maurer was elected as president of the Pennsylvania Federation of Labor, a post which he held until 1930. Defeated in his bid for re-election to the Pennsylvania House in 1913, he came back from the loss to win election to two more terms, in 1915 and 1917. During his second and third terms of office, he was instrumental in working for the passage of child labor and workmen's compensation legislation in the state.

In January 1916, Maurer was part of a three-person delegation to President Woodrow Wilson to advocate part of the Socialist Party's peace program, proposing that "the President of the United States convoke a congress of neutral nations, which shall offer mediation to the belligerents and remain in permanent session until the termination of the war". A resolution to this effect had been offered in the House of Representatives by the SPA's only congressman, Meyer London of New York, and Wilson received London, Maurer and the party leader, Morris Hillquit, at the White House, along with various other delegations.

Maurer was the only member of the Pennsylvania legislature to vote against a resolution supporting American severance of diplomatic relations with Germany in the run up to American entry into the war. When he attempted to explain his voting rationale on the floor, Maurer was rudely shouted down by his colleagues and ruled out of order by the chair.