The book is part of the Austen Project which sees modern authors reinterpret Austen's work with Joanna Trollope's Sense and Sensibility due out this month and crime novelist Val McDermid's version of Northanger Abbey out next year.
Edinburgh-based McCall Smith is the author of The No.1 Ladies' Detective Agency series which was made into a TV show by the BBC starring US singer Jill Scott as sleuth Precious Ramotswe.
He said: "Writing a contemporary version of Emma is both a privilege and a real challenge. It is possibly Jane Austen's most thought-provoking and interesting book. Being asked to do this is like being asked to eat a box of delicious chocolates."
Emma is one of Austen's most popular novels and the story of the spoiled young woman who fancies herself as a matchmaker has been adapted for film and television several times. The plot was also the basis for the 1995 film Clueless starring Alicia Silverstone that transferred the story to modern-day Beverly Hills.
Trollope said: "It's wonderful to hear that Alexander McCall Smith is going to take Emma on. Of all the great Austen heroines, she is the one who will benefit most from being, as it were, handled by a man, especially a man with such form in creating a heroine. I can't, wait to see his take on this."