What was Dr. Seuss's last children's book published before his death?

Dr. Seuss’s last children’s book published before his death was Oh, the Places You’ll Go!

Random House first published the picture book on January 22, 1990. Written and illustrated by Theodor Seuss Geisel, it presents life as a journey filled with choices, setbacks, waiting, discovery, and possibility. The unnamed protagonist is often understood as representing the reader.

Geisel died on September 24, 1991, so this was the final book published during his lifetime. It followed You’re Only Old Once! from 1986 and became especially popular as a graduation and milestone gift. Its second-person narration—speaking directly to “you”—helps explain why it works for readers of many ages.

The main source of confusion is the existence of later Seuss books. What Pet Should I Get?, for example, was published posthumously in 2015 from an unfinished manuscript discovered after Geisel’s death. That later publication does not change the answer: Oh, the Places You’ll Go! was his final children’s book released before he died.