Kanté will initially link up with Dortmund's U19 side at their Brackel training base, though the club believe he has the potential to eventually break into the first team. He is already being described in some quarters as a wonderkid.
Thomas Broich, sporting director of Dortmund's academy, said: "Liam is a defender with a very good feel for the game – he's strong in duels and has the composure on the ball that's needed. We're convinced he'll take the next big step with us."
The left-footed defender was most recently playing for Lokomotiva Zagreb's youth side after coming through the Croatian club's academy, having initially been spotted playing for HASK before former Dinamo Zagreb midfielder Mathias Chago steered him towards Lokomotiva.
His performances attracted a host of admirers, with reported interest from Bayern Munich, TSG Hoffenheim and clubs in Italy, though Borussia Dortmund won the race for his signature.
Born in Zagreb to a Croatian mother and Malian father, Kanté has already represented Croatia at youth level, winning caps for both the under-15s and under-16s.
Standing out for his technique, passing range and calmness in possession, he has drawn comparisons with some of the more promising defensive prospects to emerge from south-eastern Europe in recent years, with scouts particularly impressed by his ability to break lines with progressive passing from the back.
Dortmund's recruitment team have followed his progress closely and see him as part of the next generation of talent to come through their academy pathway, though he is not expected to be fast-tracked into first-team contention in the immediate future.
The club have a strong recent record of developing young defenders and attackers alike into first-team and international standard, and Kanté will be hoping to follow a similar path over the coming seasons.