Gilliland, 18, will again drive the No. 4 Toyota after he made 19 starts in the series last year.
The son of former Cup driver David Gilliland missed four of the first six races last year due to age restrictions at certain tracks.
The two-time K&N Pro Series West champion placed 10th in the standings after earning four top fives and nine top 10s. His best finish was second at Gateway Motorsports Park.
He was one lap away from winning the playoff race at Texas Motor Speedway before he ran out of gas and gave up the lead to Justin Haley.
“I’m excited to be returning to the seat of the No. 4 Tundra at Kyle Busch Motorsports in 2019 and looking to build on the momentum that we had going at the end of 2018,” Gilliland said in a press release. “Last year we definitely had some high points and low points, so my goal is to be more consistent throughout the season.
“After being so close a couple times last year, I’m confident that I’ll be able to find victory lane this year and once that happens more wins will follow. I’m ready to reward everyone at JBL, Mobil 1, Toyota and TRD for their continued support.”
Gilliland will be sponsored by JBL, part of the HARMAN portfolio of audio brands, and Mobil 1.