- For the real year, see 1990 (production).
The following events took place in 1990:
- February 24 (alternate) – One year after his daughter Laura's disappearance, Leland Palmer shoots himself in his parked car by White Tail Falls.
- c. March 31 – Bobby and Shelly Briggs are wed during a weekend vacation in Reno, Nevada.
- c. October – Shelly gives birth to a daughter, Rebecca.
- c. October – Rebecca "Becky" Briggs