Charlie's Angels: Season Four was the fourth season to Charlie's Angels. The season starred Jaclyn Smith, Cheryl Ladd, David Doyle, and introduced Shelley Hack as Tiffany Welles, the newest member of the team, as a police graduate from Boston. Original Angel Farrah Fawcett also appears in three episodes. Season Four originally aired from September 12, 1979 to May 7, 1980.

It was during this season that ratings had fallen, but still remained in the top 20; some believing Shelley Hack was to blame, others are of the opinion that the change in format from team oriented episodes to episodes that focused on one angel caused the rating decline. This season also has the only episode of the entire series with no Charlie. Shelley Hack as Tiffany Welles became the favorite angel of all, for be the most professional and classy than the other, who started to act a little to unprofessional after Sabrina Duncan departure.