Herman Matinpoika "Hermanni" Pihlajamäki (11 November 1903 – 4 June 1982) was a Finnish wrestler.
He competed in freestyle wrestling at the 1932 and 1936 Olympics and won a gold and a bronze medal, respectively.
At the European championships he won a freestyle gold medal in 1931, and two silver medals in 1935, in freestyle and Greco-Roman wrestling.Pihlajamäki won six Finnish titles: in 1927, 1930, 1932 and 1935–1937, five of them in freestyle wrestling.
He worked as a policeman.
His cousin Kustaa was also a policeman and an Olympic champion in wrestling.