Bert Dietz (born 9 February 1969) is a German former racing cyclist.

[2] In 1993, Dietz became national amateur road race champion in Germany, and became professional cyclist for Team Telekom.

The biggest win of his career came already in 1995, when he won the queen stage in the Vuelta a España; he had ridden in the attack that day and was caught by leader Laurent Jalabert, but Jalabert allowed Dietz to finish first.

In 1996, Dietz was second in the Tour of Sweden, and in 1997 he won a stage in the Vuelta an Aragon.

On 21 May 2007, Dietz admitted in a TV-show for ARD that he had regularly used EPO since 1995, helped by the staff and medical team of the Telekom team.