In baseball parlance, an inside-the-park home run is a play where a hitter scores a home run without hitting the ball out of play. Inside-the-park home runs are rare events, generally occurring only a handful of times during any given season. The play requires both a fast base runner and often some sort of fielding mishap by the defense, or a strange bounce in the outfield. If the fielder commits an error during the act, however, the play is not scored as a home run, but rather advancing on an error.

An inside-the-park grand slam is the same event but, like a grand slam, features the bases loaded for an inside-the-park home run. Even more rare than an inside-the-park home run, there have only been 40 inside-the-park grand slams in Major League Baseball since 1950 and only eight since 1990 (as of 2002). Honus Wagner had the most in MLB history with five.

Of the 154,483 home runs hit from 1951 - 2000, 975 (about one in every 158) were inside the park. The percentage has dwindled over the years with the growing propensity of smaller parks.

The record for most inside-the-park home runs for a single season was set by Sam Crawford in 1901. He is also the holder for most career inside-the-park home runs with 51. The career leader post-1950 is 13 by former Royals outfielder Willie Wilson .

Jimmy Sheckard completed a phenomenal feat in 1901, hitting inside-the-park grand slams in consecutive games on consecutive days with the Brooklyn Superbas (later the Brooklyn Dodgers). Sheckard is the only person in Major League Baseball history to do so.

A rare event occurred on July 13, 1896, when Ed Delahanty of the Philadelphia Phillies hit four inside-the-park home runs against the Chicago Cubs. It's considered one of the most challenging records in baseball game.