Koi wo Shichaimashita! (恋をしちゃいました!; I Fell in Love!) is the sixth single by Morning Musume subgroup Tanpopo. It was released on February 21, 2001 on the Zetima Records label. The first press edition contained a limited-edition trading card.
The songs from this single are featured on the compilation album All of Tanpopo. "Koi o Shichaimashita" is the second track on the disk, while "Baby Cry" is the eleventh track. The music video for the single is featured on Tanpopo Single V Clips ①. "Koi wo Shichaimashita!" peaked at #2 on the Oricon weekly single chart and sold a total of 386,830 copies. It ranked as the #47 single for 2001.