Thomas Frognall Dibdin, English bibliographer, born at Calcutta, was the son of Thomas Dibdin, the sailor brother of Charles Dibdin.
Dibdin was orphaned at a young age. His father died in 1778 while returning to England and his mother died one of the following two years, and an elderly maternal aunt eventually assumed responsibility for Dibdin. He was educated at St John's College, Oxford, and studied for a time at Lincoln's Inn. After an unsuccessful attempt to obtain practice as a provincial counsel at Worcester, he was ordained a clergyman at the close of 1804, being appointed to a curacy at Kensington. It was not until 1823 that he received the living of Exning in Sussex. Soon afterwards he was appointed by Lord Liverpool to the rectory of St Mary's, Bryanston Square, which he held until his death.
The first of his numerous bibliographical works was his Introduction to the Knowledge of Editions of the Classics, which brought him under the notice of the second Earl Spencer, to whom he owed much important aid in his bibliographical pursuits. The rich library at Althorp was thrown open to him; he spent much of his time in it, and in 1814–1815 published his Bibliotheca Spenceriana. As the library was not open to the general public, the information given in the Bibliotheca was found very useful, but since its author was unable even to read the characters in which the books he described were written, the work was marred by the errors which more or less characterize all his productions. This fault of inaccuracy however was less obtrusive in his series of playful, discursive works in the form of dialogues on his favourite subject, the first of which, Bibliomania, was republished with large additions in 1811, and was very popular, passing through numerous editions.