John MacVicar FRFPSGlas FRCOG (6 November 1927 – 23 March 2011) was a British physician who was most notable for pioneering the diagnostic use of ultrasound in obstetrics as well as later, being a clinical educator.

[1] MacVicar was part of a team along with physician Ian Donald and engineer Tom Brown, who developed the worlds first obstetric ultrasound machine in 1963.

Using the new technique of ultrasound, MacVicar's research transformed the treatment of gynaecological conditions in pregnant women,[2] through the use of clinical trials.

[4] After a number of junior positions, MacVicar spent 2 years abroad in Singapore for his National service working as a medical officer for the wives of serviceman.

[4] When he returned, he was appointed to a position at Stobhill Hospital, which enabled him to complete his membership exam for the Royal College of Obstetricians and Gynaecologists.