Sir Prafulla Chandra Ray CIE FNI FRASB FIAS FCS (also spelled Prafulla Chandra Roy; Bengali: প্রফুল্ল চন্দ্র রায় Prôphullô Côndrô Rāẏ; 2 August 1861 – 16 June 1944) was a Bengali chemist, educationist, historian, industrialist and philanthropist. He established the first modern Indian research school in chemistry (post classical age) and is regarded as the Father of Indian Chemistry.

The Royal Society of Chemistry honoured his life and work with the first ever Chemical Landmark Plaque outside Europe. He was the founder of Bengal Chemicals & Pharmaceuticals, India's first pharmaceutical company. He is the author of A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century (1902).

Prafulla Chandra Ray was born in the village of Raruli-Katipara, then in Jessore District (now Paikgachha, Khulna), in the eastern region of the Bengal Presidency of British India (now Bangladesh) to a Bengali Hindu family. He was the third child and son of Harish Chandra Raychowdhury (d. 1893), a Kayastha zamindar and his wife Bhubanmohini Devi (d. 1904), the daughter of a local taluqdar. Ray was one of seven siblings, having four brothers – Jnanendra Chandra, Nalini Kanta, Purna Chandra and Buddha Dev – and two sisters, Indumati and Belamati, both born after their brothers. All except Buddha Dev and Belamati survived to adulthood.

Ray's great-grandfather Maniklal had been a dewan under the British East India Company's district collector of Krishnanagar and Jessore, and had amassed considerable wealth in the service of the company. After succeeding to his father's post, Ray's grandfather Anandlal, a progressive man, sent his son Harish Chandra to receive a modern education at Krishnagar Government College. At the college, Harish Chandra received a thorough grounding in English, Sanskrit and Persian, though he was ultimately forced to end his studies to help support his family. Liberal and cultured, Harish Chandra pioneered English-medium education and women's education in his village, establishing both a middle school for boys and one for girls, and admitting his wife and sister to the latter. Harish Chandra was strongly associated with the Brahmo Samaj, and Ray would maintain his connections with the Samaj throughout his life.

After recovering from an illness, Ray moved to Calcutta in 1876 and was admitted to the Albert School, established by the Brahmo reformer Keshub Chandra Sen; owing to his concentrated self-study over the preceding two years, his teachers found him to have advanced much further than the rest of the students in his assigned class. During this period, he attended Sen's Sunday evening sermons and was deeply influenced by his Sulabha Samachar. In 1878, he passed the school's Entrance Examination (matriculation exams) with a First Division, and was admitted as an FA (First Arts) student to the Metropolitan Institution (later Vidyasagar College) which was established by Pandit Ishwar Chandra Vidyasagar. The English literature teacher at the Institution was Surendranath Banerjee, the prominent Indian nationalist and future president of the Indian National Congress, whose passionately held ideals, including an emphasis on the value of service and the need to continually strive for India's rejuvenation, left a definite and lasting impression on Ray, who took those values to heart. While deeply influenced by Sen, Ray preferred a more democratic environment than the mainstream Brahmo Samaj under Sen's guidance could provide; consequently, in 1879 he joined the Sadharan Brahmo Samaj, a more flexible offshoot of the original Samaj.

Though Ray had primarily focused on history and literature until this stage, chemistry was then a compulsory subject in the FA degree. As the Metropolitan Institution offered no facilities for science courses at the time, Ray attended physics and chemistry lectures as an external student at the Presidency College. He was especially drawn to the chemistry courses taught by Alexander Pedler, an inspiring lecturer and experimentalist who was among the earliest research chemists in India. Soon captivated by experimental science, Ray decided to make chemistry his career, as he recognized that his country's future would greatly depend on his progress in science. His passion for experimentation led him to set up a miniature chemistry laboratory at a classmate's lodgings and reproducing some of Pedler's demonstrations; on one occasion, he narrowly escaped injury when a faulty apparatus exploded violently. He passed the FA exam in 1881 with a second division, and was admitted to the BA (B-course) degree of the University of Calcutta as a chemistry student, with a view towards pursuing higher studies in the field. Having learnt Latin and French in addition to achieving a "fair mastery" of Sanskrit, a compulsory subject at the FA level, Ray applied for a Gilchrist Prize Scholarship while studying for his BA examination; the scholarship required a knowledge of at least four languages. After an all-India competitive examination, Ray won one of the two scholarships, and enrolled as a BSc. student at the University of Edinburgh without completing his original degree. He sailed for the United Kingdom in August 1882, aged 21.

At Edinburgh, Ray began his chemistry studies under Alexander Crum Brown and his demonstrator John Gibson, a former student of Brown's who had also studied under Robert Bunsen at the University of Heidelberg. He received his BSc. in 1885. During his student years at Edinburgh, Ray continued to nurture his strong interests in history and political science, reading works by prominent authors including Rousselet's L'Inde des Rajas, Lanoye's L'Inde contemporaine, Revue dex deux mondes. He also read Fawcett's book on political economy and Essays on Indian Finance. In 1885, he entered an essay competition held by the university for the best essay on "India before and after the Mutiny." His submission, which was strongly critical of the British Raj and warned the British government of the consequences of its reactionary attitudes, was nonetheless assessed as one of the best entries and was highly praised by William Muir, the recently appointed Principal of the University and a former lieutenant-governor of the North-Western Provinces in India. Ray's essay was widely publicised in Britain, with The Scotsman observing "It contains information in reference to India which will not be found elsewhere, and is deserving of the utmost notice." A copy of the paper was read by the distinguished orator and Liberal Member of Parliament for Birmingham John Bright; Bright's sympathetic reply to Ray was published in leading newspapers across Britain under the title "John Bright's Letter to an Indian Student." The following year, Ray published his paper as a booklet entitled "Essay on India," which likewise earned its author wide attention in British political circles.

After obtaining his BSc degree, Ray embarked on his doctoral studies. Although his thesis advisor Crum Brown was an organic chemist, Ray was drawn towards inorganic chemistry at a time when research in the field appeared to be making limited progress compared to organic chemistry. Following an extensive review of available inorganic chemistry literature, Ray decided to explore the specific natures of structural affinities in double salts as the subject of his thesis. Within this area, Ray chose to research metal double sulfates.