Karin Balzer (born June 5, 1938) is a former East German hurdler, one of the best in high hurdles event during the 1960s.

She was born Karin Richert in Magdeburg, and competed in several track and field events when she was young. However, the 80 m hurdles appeared to be her best event, and she qualified for the German team for the 1960 Summer Olympics. At the time, the team was still made up from athletes of both East and West Germany. She narrowly missed qualification for the final.

The following year, she married her coach, former pole vaulter, Karl-Heinz Balzer. Some years earlier, they had briefly fled the DDR, but had returned weeks later. Now competing as Karin Balzer, she won her first international medal, silver at the 1962 European Championships. In 1964, she tied the world record in the high hurdles during a pentathlon competition. Although her score in that event was also excellent, she never competed in that event in major meets.

At the Tokyo Olympics that same year, she placed for the final of the 80 m hurdles. In an amazingly close finish, the first three runners all timed 10,5, equal to the world record (although there had been a wind advantage, meaning the record was not ratified). Electronic timing showed Balzer had beaten the two other medallists by one and two hundredths of a second, respectively.

Two years later, Balzer won a second title at the European Championships, and she placed fifth in the 1968 Olympic final. That was the last major event in which the high hurdles were run over 80 m; from 1969 on, the event became the 100 m. Balzer set the inaugural world record in that event, in June 1969, but would lower it two more times that year. She also successfully defended her European title in Athens, which she repeated in Helsinki two years later.

While in training for the 1972 Summer Olympics in Munich, Balzer's son, Andreas was involved in an accident, and was comatised. He passed away the day before the final of the 100 m hurdles, but her husband did not tell her until after the race, in which she won her second Olympic medal, bronze.

Balzer's second son, Falk Balzer also became a hurdler. His best achievement is a second place in the 110 m hurdles at the 1999 European Championships.