The 25-year-old has signed a five year deal.
Rob Elliot: "I am looking forward to the challenge of joining a club like Newcastle United.
"This is a huge club and a huge opportunity for me to learn from two of the best keepers in the division."
Alan Pardew: "The goalkeeping position is one we felt we needed to strengthen.
"Rob is an excellent keeper who I have worked with before, and I know he will be a good signing for the club."