The couple welcomed their third child on Monday, Nov. 23. The 28-year-old actress announced the news on her Instagram page.
"Saylor James Cutler was born today at 132pm!!" Cavallari wrote in the photo post, which shows a pink onesie, bows and inked footprints.
Saylor joins big brothers Camden Jack, 3, and Jaxon Wyatt, 18 months.