Ralph Oscar Yeager, AIA, (1892 – 1960) was an American architect who worked in Indiana.^[1] He was a partner in the Terre Haute, Indiana, architectural firm of Miller & Yeager and the Indianapolis, Indiana, architectural firm of Vonnegut, Wright & Yeager.^[2]

Yeager was born August 16, 1892, in Danville, Illinois, where he graduated from high school. He then attended the School of Architecture at the University of Illinois for two years (1911–1913) and then earned a Bachelor of Science degree in architecture for the University of Pennsylvania, class of 1915.

Yeager supervised construction on the U.S. Post Office Building (1915–1917) for Yeager & Sons, Contractors, served as a second lieutenant in the army during World War I (1917–1918), and was variously employed architectural offices in Chicago, Terre Haute, and Madison, Wisconsin. In 1922, he established his own practice in Chicago before returning to Terre Haute the next year (1923) to become a partner in the firm Miller & Yeager.

Miller & Yeager, located at 402 Opera House Building, Terre Haute, Indiana, was responsible for many landmarks in Indianapolis and greater Indiana, and a number have been listed on the National Register of Historic Places.

In 1946, he was the sole surviving partner of Miller & Yeager and merged the firm with Vonnegut, Bohn & Mueller and Pierre & Wright, both of Indianapolis, Indiana.^[2]

He was the president of the Indiana Society of Architects in 1937, 1945–1946, the Indiana chapter of the American Institute of Architects in 1945-1946, member of the Indian Society of Architects from 1923 and chapter of the AIA since 1926 (the two merged in 1946), director of the Great Lakes District of the AIA in 1946-7.