Claes de Frietzcky (25 January 1727 – 9 October 1803) was a Swedish politician.

He was the eight and youngest son of Johan de Frietzcky and Anna Elisabeth Linroth.

He was a skilled business owner but left this profession to engage in politics.

He became one of the leading people of the Caps party and during the transformations of the Swedish state in 1772, he joined the aristocratic opposition, which defended the rights of the Swedish Parliament towards the king.

He became the main opponent to Gustav III in the issue of alcohol.