Jakob Bernoulli (Basel, December 27, 1654 - August 16, 1705), also known as Jacob, Jacques or James Bernoulli was a Swiss mathematician and scientist and the older brother of Johann Bernoulli.

Jakob Bernoulli met Robert Boyle and Robert Hooke on a trip to England in 1676, after which he devoted his life to science and mathematics. He lectured at the University of Basel from 1682, becoming Professor of Mathematics in 1687.

He corresponded with Gottfried Leibniz, and thus learnt calculus, and collaborated with his brother Johann. His early papers on transcendental curves (1696) and isoperimetry (1700, 1701) are early examples of its application.

His masterwork was Ars Conjectandi (the Art of Conjecturing), a groundbreaking work on probability theory. It was published eight years after his death in 1713 by his nephew Nicholas. The terms Bernoulli trial and Bernoulli Numbers result from this work, and are named after him.