Mungo Park was born in Selkirkshire, Scotland, at Foulshiels on the Yarrow Water, near Selkirk, on a tenant farm which his father rented from the Duke of Buccleuch. He was the seventh in a family of thirteen. Although tenant farmers, the Parks were relatively well-off. They were able to pay for Park to receive a good education, and Park's father died leaving property valued at £3,000 (equivalent to $222,289 in 2016). His parents had originally intended him for the Church of Scotland.
He was educated at home before attending Selkirk grammar school. At the age of fourteen, he was apprenticed to Thomas Anderson, a surgeon in Selkirk. During his apprenticeship, Park became friends with Anderson's son Alexander and was introduced to Anderson's daughter Allison, who would later become his wife.
In October 1788, Park enrolled at the University of Edinburgh, attending for four sessions studying medicine and botany. Notably, during his time at university, he spent a year in the natural history course taught by Professor John Walker. After completing his studies, he spent a summer in the Scottish Highlands, engaged in botanical fieldwork with his brother-in-law, James Dickson, a gardener and seed merchant in Covent Garden. In 1788 Dickson along with Sir James Edward Smith and six other fellows founded the Linnean Society of London.
In 1792 Park completed his medical studies at University of Edinburgh. Through a recommendation by Banks, he obtained the post of assistant surgeon on board the East India Company's ship Worcester. In February 1793 the Worcester sailed to Benkulen in Sumatra. Before departing, Park wrote his friend Alexander Anderson in terms that reflect his Calvinist upbringing:
My hope is now approaching to a certainty. If I be deceived, may God alone put me right, for I would rather die in the delusion than wake to all the joys of earth. May the Holy Spirit dwell in your heart, my dear friend, and if I ever see my native land again, may I rather see the green sod on your grave than see you anything but a Christian.