Sir William Robert Grove, FRS FRSE (11 July 1811 – 1 August 1896) was a Welsh judge and physical scientist. He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology. He invented the Grove voltaic cell.

Born in Swansea, Wales, Grove was the only child of John, a magistrate and deputy lieutenant of Glamorgan, and his wife, Anne (née Bevan).

His early education was in the hands of private tutors, before he attended Brasenose College, Oxford to study classics, though his scientific interests may have been cultivated by mathematician Baden Powell. Otherwise, his taste for science has no clear origin though his circle in Swansea was broadly educated. He graduated in 1832.^{[citation needed]}

In 1835, he was called to the bar by Lincoln's Inn. In the same year, Grove joined the Royal Institution and was a founder of the Swansea Literary and Philosophical Society, an organisation with which he maintained close links.

In 1829, at the Royal Institution, Grove met Emma Maria Powles.^{[dubious – discuss]}. They married in 1837.

The couple embarked on a tour of the continent for their honeymoon. This sabbatical offered Grove an opportunity to pursue his scientific interests and resulted in his first scientific paper suggesting some novel constructions for electric cells.

During 1839, Grove developed a novel form of electric cell, the Grove cell, which used zinc and platinum electrodes exposed to two acids and separated by a porous ceramic pot. Grove announced the latter development to the Académie des Sciences in Paris in 1839. In 1840 Grove invented one of the first incandescent electric lights, which was later perfected by Thomas Edison.

Later that year, he gave another account of his development at the British Association for the Advancement of Science meeting in Birmingham, where it aroused the interest of Michael Faraday. On Faraday's invitation Grove presented his discoveries at the prestigious Royal Institution Friday Discourse on 13 March 1840.