Monika Cassens (née Thiere, born 28 February 1953) is a German former badminton player.

For this club she won 15 national titles.

After her marriage to Claus Cassens, she changed to SG Gittersee, a badminton club in Dresden.

She won 6 Polish Open titles in a row in women's singles and women's doubles, and six titles in mixed doubles.

This biographical article relating to German badminton is a stub.