In 2010 Prof Muller was the first recipient of the Lifetime Achiever Award of the South African Association of Political Scientists (SAAPS), in recognition of her contribution to the discipline of International Relations. She trained many of the senior Political Science academics in South Africa and was the first woman International Relations lecturer at both UNISA and the University of Pretoria. Her research contributions covered the field of regional integration in Southern Africa and various aspects of diplomatic studies, with a more recent focus on South Africa's economic diplomacy. She was a past president of SAAPS and of the prestigious International Pugwash Council. She was also a member of the Academy of Science of South Africa (ASSAf) and the South African Academy for Science and Arts.

Her funeral service will take place at 10:00 on Friday, 8 March 2013, in the Dutch Reformed Church, Pretoria East. The church is situated to the west of the Loftus Versfeld Stadium.