Sekiguchi (written: 関口) is a Japanese surname. Notable people with the surname include:
Fusao Sekiguchi Japanese industrialist Gen Sekiguchi Japanese film director Hisao Sekiguchi Japanese footballer , Japanese skier Hideaki Sekiguchi, known as "Billy" or "Bass Wolf", original bassist for Japanese rock band Guitar Wolf Kazuyuki Sekiguchi Japanese musician Kunimitsu Sekiguchi Japanese footballer Mai Sekiguchi Japanese actress Masakazu Sekiguchi Japanese politician Taro Sekiguchi Japanese motorcycle racer Yuhi Sekiguchi Japanese race driver The Sekiguchi Corporation invented the Monchhichi doll.