Shigeki Maruyama (丸山茂樹, Maruyama Shigeki; born 12 September 1969) is a Japanese professional golfer.
Maruyama was born in Chiba. He attended Nihon University and turned professional in 1992. He is known for his ever-present smile on the golf course which has given rise to his nickname of the "Smiling Assassin". He began his career on the Japan Golf Tour, quickly becoming one of the leading players on that tour. Two excellent finishes in World Golf Championships events in 1999 helped to earn him membership of the U.S. based PGA Tour for the 2000 season, and he has played mainly in America since then. He has three PGA Tour victories. At the end of the 2008 season he announced he was returning to Japan after failing to maintain full playing rights on the PGA Tour.
Maruyama was a member of The International Team in the Presidents Cup in 1998 and 2000. His performance in 1998 brought him worldwide attention as he was the star performer in the tournament with a 5-0-0 win-loss-tie record.