Merja Lahtinen (born 1968) is a former Finnish cross country skier who competed from 1992 to 1998. Competing at the 1994 Winter Olympics in Lillehammer, she had her best finish of fourth in the 4 x 5 km relay and her best individual finish of 15th in the 30 km event.
Lahtinen's best finish at the FIS Nordic World Ski Championships was tenth in the 15 km event at Thunder Bay, Ontario in 1995. Her best world Cup finish was 11th twice, both in Finland (1992, 1995).
Lahtinen's best individual career finish was second twice in 5 km FIS races in Finland (1994, 1997).