Sir Edward Frankland, KCB, FRS, FRSE (18 January 1825 – 9 August 1899) was an English chemist. He was one of the originators of organometallic chemistry and introduced the concept of combining power or valence.

An expert in water quality and analysis, he was a member of the second royal commission on the pollution of rivers, and studied London's water quality for decades. He established the then revolutionary possibility of biological treatment of sewage using a contact bed to oxidize the waste. This concept was taken up by the chief chemist for the London Metropolitan Board of Works, William Dibdin, in 1887.

He also studied luminous flames and the effects of atmospheric pressure on dense ignited gas, and was one of the discoverers of helium.

Edward Frankland was born in Catterall, Lancashire and baptised at Churchtown, Lancashire on 20 February 1825. As his baptismal record shows, his birth was illegitimate. His natural father was Edward Chaddock Gorst, the father of John Eldon Gorst. His mother, Margaret "Peggy" Frankland, later married William Helm, a Lancaster cabinet-maker. "His illegitimacy cast a shadow over all his life since he was pledged to silence as to the identity of his natural father, although a handsome annuity was paid to his mother".

From age 3 to 8 Edward lived and was educated in Manchester, Churchtown, Salford and Claughton. In 1833, the family moved to Lancaster and he attended the private school of James Wallasey, where he first took an interest in chemistry, in particular, reading the work of Joseph Priestley borrowed from the Mechanics Institute Library.

At age 12, Edward moved to the Lancaster Free Grammar School (later Lancaster Royal Grammar School), that had also educated scientists William Whewell and Sir Richard Owen. According to Frankland himself, his interest in chemistry was furthered by a case held in the court of Lancaster Castle, which was adjacent to the Free Grammar School (then located on Castle Hill, Lancaster). It was an action brought by the Corporation of Liverpool against Mr Muspratt for committing a nuisance by allowing muriatic acid gas (HCl) to escape from his chemical works in Liverpool. "I was already much interested in chemistry, my step-father allowed me to stay away from school in order to attend the trial" Frankland wished to become a doctor, but the cost of training was "absolutely prohibitive". So the only entrance for him was "the back door of a druggist's shop"

In 1840, Edward was indentured by his step-father, William Helm as an apprentice to Stephen Ross, a Lancaster pharmacist. and his duties included "mortar and pestle work", pounding and mixing large quantities of chemicals to create medicinal preparations such as ointments.

During the latter part of his six-year apprenticeship, Frankland also attended the Lancaster Mechanics' Institute (later to become The Storey, attending classes in a makeshift cottage laboratory made available to local apprentices and other young men by a local doctor, James Johnson. Others in that youthful circle were the scientific writer Robert Galloway (also apprenticed to Ross) and the anatomist William Turner. With support and encouragement from Johnson, Frankland acquired, in 1845, a place in the Westminster laboratory of Lyon Playfair, 1st Baron Playfair. Whilst there, Frankland attended Playfair's lecture course; at the end of it he passed the examination—the only written one he ever sat.