It was unclear when the event started or how many were in attendance but reporters saw dozens of people walking from a church to another building. Soft music could be heard coming from there later.
Apple spokesman Todd Wilder tells reporters he's been there since 2 p.m. PDT. He says it's a private event and he can't release any details about it. Stanford has also declined comment.
Earlier, guards directed the handful of reporters to a parking lot several hundred yards away from Stanford's Memorial Church where the service was held.
Additional personnel behind steel barricades allowed only a smattering of vehicles to enter the area.
Jobs was the mastermind behind popular gadgets such as the iPhone and iPad. He died Oct. 5 at age 56 after struggling for years with pancreatic cancer.