| Hilgard Muller | |
| Office: | Minister of Foreign Affairs |
| Term Start: | 9 January 1964 |
| Term End: | 1 April 1977 |
| Predecessor: | Eric Louw |
| Successor: | Pik Botha |
| Office2: | South African Ambassador to Portugal simultaneously accredited to Spain |
| Term Start2: | 1958 |
| Term End2: | 1961 |
| Office3: | South African Ambassador to the United Kingdom |
| Term Start3: | 1961 |
| Term End3: | 1964 |
| Birth Date: | 1914 5, df=yes |
| Birth Place: | Potchefstroom |
| Death Place: | Pretoria, South Africa |
| Party: | National Party |
| Alma Mater: | University of Oxford |
| Occupation: | Lawyer |
Hilgard Muller, (4 May 1914 - 10 July 1985)[1] was a South African politician of the National Party, Mayor of Pretoria in 1953 - 1955, elected an MP in 1958, appointed Minister of Foreign Affairs[2] after the resignation of Eric Louw in 1964. He relinquished both posts in 1977. Studying at the University of Pretoria, he obtained a Rhodes Scholarship at the University of Oxford, earning a doctorate in law. Practicing law in Pretoria, he was elected to Pretoria city council in 1951, becoming Mayor of the city two years later. He relinquished his city council seat in 1957, being elected to House of Assembly the following year for Pretoria East. He chose not to run for his seat again in 1961, instead being appointed South African ambassador in London, but returned to parliament in 1964 immediately to be appointed Minister of Foreign Affairs.
Muller retired to private life in 1977 and was succeeded by Frederik Roelof "Pik" Botha, who kept the post until multi-racial elections in 1994.