The 34-year-old previously played for Rangers during the 2000-01 season and enjoyed a hugely successful second spell with the club between 2008 and 2011.
Miller won three league titles, the Scottish Cup and the League Cup during Walter Smith's reign before leaving for Bursaspor in January 2011.
And he now returns to try and score the goals to send Rangers into the Scottish Premiership after spells with Cardiff and the Vancouver Whitecaps.
He said: "I am thrilled to return to Rangers for a third time.
"I have enjoyed so much success at this great football club and I am determined to repeat it again next season and beyond.
"Rangers is a special football club and we are on the rise again and I want to play my part as we look to get back to the top of Scottish football.
"I had a number of offers once I left Vancouver but I had my heart set on returning to Ibrox and I can't wait to get started again."
Boss Ally McCoist added: "We are delighted to welcome Kenny back to Ibrox.
"He was a terrific player for us in the past, especially his second spell at Rangers, and we have won many trophies together.
"Kenny brings experience and pace to our forward line and will be a great influence on our younger players at Murray Park. He is a top class footballer and we look forward to seeing him in a Rangers jersey once again as we look to secure promotion to the top flight next season."