A batting helmet is worn by batters in the game of baseball or softball. It is meant to protect the batter's head from errant pitches thrown by the pitcher. A batter who is "hit by pitch," due to an inadvertent wild pitch or by intent, may be seriously, even fatally, injured.

In 1905, Mogridge created the first crude protective headgear and was granted patent No. 780899 for a "head protector." This first attempt at a batting helmet was said to look like an "inflatable boxing glove that wrapped around the hitters head." Roger Bresnahan, Hall of Fame catcher who was injured after being struck in the head with a pitch, developed a leather batting helmet in 1908 which he began using. These were not so much helmets as protective earmuffs. They did not protect the batter's head but rather protected the ear and temple region. He also developed an aluminum protector for the back of the head that was covered in fake hair, but it is unknown whether it was used in the field.

In 1908, Chicago White Sox shortstop Freddy Parent wore a head protector of some sort and Chicago Cubs' first baseman-manager Frank Chance did the same thing in 1913, though Chance's headgear was "little more than a sponge wrapped in a bandage." In 1914, minor leaguer Joe Bosk, playing for the Utica Utes, wore a protector after being severely injured when he was struck in the head by a pitch in 1911.

Despite the fatal beaning of Ray Chapman in 1920, protective headgear was still used only rarely in the major leagues. That year, a syndicated news article claimed several baseball executives—including New York Giants secretary Frank McQuade—were trying to mandate the use of batting helmets. The article also asserted helmets were unpopular among players. The first known case of a manager issuing head protectors to his players on a large scale was Philadelphia Phillies' manager Pat Moran who gave cork-cushioned hats to his players in 1921. Connie Mack, manager of the Philadelphia Athletics, voiced his support for protective headgear in 1921.

In 1936, Willie Wells, a Negro leagues player, was knocked unconscious with a pitch to the temple. Disregarding the doctor's advice to sit out, Wells wore a modified construction hard hat as protective gear in a game the next day.

After Mickey Cochrane, a Hall of Fame catcher for the Detroit Tigers, suffered a career-ending and near-fatal skull fracture on May 25, 1937, on a pitch by New York Yankees' pitcher Bump Hadley, there was a strong call for batter helmets. Cochrane himself went on record saying that players should "absolutely" be required to wear protective helmets.

Only one week after Cochrane's injury, on June 1, 1937, the Cleveland Indians and Philadelphia Athletics became the first teams to test helmets, using leather and polo helmets respectively. Managers of both teams decided to use batting practice as a test run for helmet use on their players, before a game between the two teams. Though there is picture evidence of the polo helmets being worn in batting practice, there is no evidence of their being used or worn in a game. The first documented team to wear helmets in a game was the Des Moines Demons of the Western League. They also used polo helmets but the idea did not stick, as they only wore the helmets for one game.

The first professional baseball league to fully adopt the baseball helmet was the International League, which did so in 1939 when the list of official equipment used began to include a "safety cap or helmet". Buster Mills was the first player in the league to use a helmet.