Has an MLB game ever ended 18-1?
It has. 18-1 has been a MLB final 33 times in 235,971 games. The first was Providence Grays beat New York Gothams on July 5, 1883; the latest was Houston Astros beat Los Angeles Dodgers on July 4, 2025.
That makes 18-1 the 155th most common final score out of 330 that have ever occurred in MLB. One point away, 19-1 has happened 22 times and 18-2 has happened 47 times. At one point the score disappeared for 33 years, between 1943 and 1976.