Frank Thelen (born 10 October 1975) is a German businessman, investor and author based in Bonn.

[1] He is best known as a former investor in the TV series Die Höhle der Löwen, the German version of Shark Tank.

[12] In 2012, Thelen spoke at the Founders Conference in New York and was given the "Innovate by Society" Award by Microsoft handed out by German Chancellor Angela Merkel that same year for his startup "doo".

[17] In 2014, he joined the German version of the TV show Dragons' Den (Shark Tank), called Die Höhle der Löwen, as investor.

[19] In 2018, his autobiography Startup-DNA – Hinfallen, aufstehen, die Welt verändern was published[20] and has been a bestseller for several weeks.