Goethe Institut
The Goethe Institut is the cultural institute of the Federal Republic of Germany and promoting knowledge of the German language is at the centre of its mandate.

The Goethe Institut also offers examinations leading to language certifications at all levels. These certifications are recognized by German universities as proof of German knowledge.
The TestDaF as well as Goethe Zertifikat C2 which are accepted proficiency tests to apply to programmes taught in German language are offered by the Goethe Institut.

For more information on the Goethe Institut, their language courses and examinations, visit:  https://www.goethe.de/ins/sg/en/index.html

Ministry of Education Language Centre (MOELC)
Students who qualify can take up German as a 3rd language at the MOELC.
http://moelc.moe.edu.sg/

Universities
As a student at the National University of Singapore (NUS) or Nanyang Technological University (NTU) you can take advantage of the German language courses offered.
https://www.fas.nus.edu.sg/cls/
http://cml.soh.ntu.edu.sg/Pages/Home.aspx

German European School Singapore and International Schools
The German European School Singapore (GESS) offers a full time German curriculum leading to the German high school diploma (Abitur). Their IB stream (International Baccalaureate) also offers German language classes.

Other International schools also offer German classes as part of their curriculum.

Polytechnics
Some Polytechnics offer German classes up to a certain level.