Alva Jo Fischer was a pitcher and shortstop who played from 1945 through 1949 in the All-American Girls Professional Baseball League. Listed at 5 ft. 9 in. (1.75 m), 135 lb., she batted and threw right-handed. 

Fischer was born in San Antonio, Texas, and played for the all-state team at first base in 1938. She entered the All-American Girls Professional Baseball League in 1945 with the Rockford Peaches, playing for them one year before joining the Muskegon Lassies for the rest of her five-year career. 

Nicknamed “Tex” by her teammates, Fischer was used primarily as a pitcher, but later became a highly competent shortstop as well. In her rookie season, Fischer posted a 4–7 record with a 3.77 earned run average and 98 innings of work in 16 pitching appearances. 

The Peaches, managed by Bill Allington, won the regular season title with a 67–43 mark. They increased their dominance during the postseason, when they defeated the Grand Rapids Chicks three to one in the best-of-five first round games, and claimed the championship by defeating the Fort Wayne Daisies four to one in the best-of-seven series. In the final series, Fischer hurled three shutout innings of relief. 

When Fischer joined the expansion Lassies in 1946, the team's manager, Buzz Boyle, experimented with her at shortstop, where she was able to use her great throwing arm while sharing duties with Dorothy Stolze. She also contributed with an 11–16 pitching record and a 2.77 ERA in 29 games. Fischer became the everyday shortstop for Muskegon in 1947. While adapting to her new role, Fischer did not pitch during the season. She committed 58 errors in 586 chances for a poor .901 fielding average, and batted only .202 in 112 games. Muskegon clinched the championship with two days remaining on the regular schedule and advanced to the postseason, only to be defeated in the best-of-five first round by Racine, three games to one. 

In 1948 Fischer improved at shortstop, showing excellent range and lowering her error rate (36) compared to the previous year and raising her fielding average to .917. She also returned to pitch and went 9–7 with a 1.47 ERA in 21 appearances, while hitting .252 with 31 runs and 36 RBIs in 107 games. In addition, her ERA was the ninth best in the league. Muskegon was upset by Fort Wayne in the best-of-five first round play-off games, three to two. Fischer was charged with one of the losses after allowing one run and five hits in six innings of work.

Fischer enjoyed a career year in 1949, her last season, when she became the best shortstop in the league with a .972 average and only 23 errors in 481 fielding chances while turning in 48 double plays. She batted only .198 in 109 games, but posted a 10–7 record with a 1.78 ERA and a career-high 86 strikeouts in 25 games pitched, ending eighth in the league for the most strikeouts. Muskegon swept Kenosha in the first round games, two to zero, but lost the second round to Grand Rapids, three to zero. Fischer shutout Kenosha with a four-hit, 3–0 victory in Game 1 of the best-of-three series. She then labored through 13 innings to Grand Rapids in the next step, allowing twelve hits and four earned runs, but did not have a decision. 

In a five-year career, Fischer posted a 34–37 record and a 2.40 ERA in 91 pitching appearances, while hitting a .223 average with 91 runs and 131 RBI in 345 games. As a fielder, she committed only 117 errors in 1,500 chances for a solid .922 average. In seven postseason games, she went 1–1 with a 1.20 ERA and hit .125 (6-for-48) in 13 games. 

Fischer died of leukemia in San Antonio, Texas, August 13, 1973 at the age of 47. Fifteen years after her death, she became part of Women in Baseball, a permanent display at the Baseball Hall of Fame and Museum at Cooperstown, New York, which was unveiled in 1988 to honor the entire All-American Girls Professional Baseball League. 

The Alva Jo Fischer Softball Complex in San Antonio was named after her in 1975. The San Antonio Sports Hall of Fame added her in 1998, and the Texas Baseball Hall of Fame followed suit in 2006.    

Burial: Mission Burial Park, South San Antonio, Bexar County, Texas.