Weldy Wilberforce Walker (July 27, 1860 – November 23, 1937), sometimes known as Welday Walker and W. W. Walker, was an American baseball player. In 1884, he became the third African American to play Major League Baseball.

Walker played at Oberlin College and the University of Michigan. In July 1884, he joined the Toledo Blue Stockings of the American Association which was then part of Major League Baseball. His brother Moses Fleetwood Walker, commonly known as Fleetwood (or "Fleet") Walker, was the second African American to play Major League Baseball, making his debut two months before Weldy. In 1887, as racial segregation took hold in professional baseball, Weldy joined the Pittsburgh Keystones of the short-lived National Colored Base Ball League.

His March 1888 open letter to The Sporting Life protesting the racial segregation of baseball has been described as "perhaps the most passionate cry for justice ever voiced by an athlete."

After retiring from baseball, Walker operated restaurants and a hotel in eastern Ohio. In 1897, he served on the Executive Committee of the Negro Protective Party, a newly formed political party established in Ohio in protest of the failure of the Republican governor to investigate the lynching of an African American in June 1897 at Urbana, Ohio. In the 1900s, Weldy and his brother Fleetwood became active in the Back-to-Africa movement and promoted emigration to Liberia. The brothers also established and edited The Equator, a black issues newspaper.

Walker was born in 1860 in Steubenville, Ohio, an industrial city in the eastern part of the state with a reputation for racial tolerance. Weldy's name was a combination of the biblical word for wealthy ("weldy") and the surname of English abolitionist William Wilberforce.

His parents, Moses W. Walker and Caroline (O'Hara) Walker, moved to Steubenville from Mount Pleasant, Ohio. His father was a minister in the Methodist Episcopal Church, a physician, and a leader in Steubenville's African-American community. In June 1870, at the time of the 1870 United States census, the Walker family was living in Steubenville's First Ward. Walker's father was identified as a minister who had been born in Virginia. The couple had four children listed in the Census: William (age 25), Mary (age 21), Sarah (age 19), Moses F. (age 11) and Weldy W. (age 9). In June 1880, at the time of the 1880 United States census, the family was still living in Steubenville and consisted of Moses (age 59, clergyman), Caroline (age 57), William (age 35, teamster), Sarah (age 22), Moses (age 21, at school), Weldan (age 19, at school), and Mary Alexander (age 13, adopted).

Weldy attended Steubenville's integrated public high school in the 1870s.

While Weldy was still in high school, his older brother, Fleetwood Walker, enrolled at Oberlin College, which was among the first colleges in the United States to become racially integrated. In 1881, Weldy joined his brother at Oberlin College, enrolling as a student in the Oberlin's preparatory school. In the spring of 1881, the Walker brothers played on Oberlin College's first varsity inter-collegiate baseball team. Weldy, a freshman, played right field while Fleetwood, a junior, was the catcher. According to one account, Weldy played second base and finished the 1881 season as Oberlin's second leading batter.