Terms of the deal were not disclosed.
Coyotes general manager Don Maloney said the 38-year-old Lang "provides another veteran presence for our team and is a proven scorer in the National Hockey League."
Lang has 252 goals and 422 assists in 925 games in his 15-year NHL career along with 18 goals and 27 assists in 87 playoff games. The Czech star was limited by injuries to 50 games last season with the Montreal Canadiens but had 18 goals and 21 assists.
He has also played for Los Angeles, Boston, Pittsburgh, Washington, Detroit and Chicago.