Johann Heinrich Zedler (7 January 1706 in Breslau (now Wrocław, Poland) – 21 March 1751 in Leipzig) was a bookseller and publisher. His most important achievement was the creation of a German encyclopedia, the Grosses Universal-Lexicon (Great Universal Lexicon), the largest and most comprehensive German-language encyclopedia developed in the 18th century.

After training as a bookseller, Zedler founded his own publishing house in 1726. It was initially based in Freiberg, Upper Saxony, and in 1727 moved to the Publishing and Book Trade Center in Leipzig. His first major publication was an eleven volume edition of the writings of Martin Luther published between 1729 and 1734, with an index volume published in 1740. As the founding publisher of the Universal-Lexicon, started in 1731 and during his lifetime growing to a total of 64 volumes, Zedler got into a long-standing legal dispute with the established publishers in Leipzig, whose more specialized products were threatened.

Some time before the spring of 1737, Zedler suffered a financial collapse. His business was bought by the Leipzig businessman Johann Heinrich Wolf. Wolf provided funding for Zedler to continue with the Universal-Lexicon and other works he had already begun such as the General Chronicle of States, Wars, Churches and Scholarship (1733–1754, 22 volumes). Zedler also published new works such as the trade lexicon Allgemeine Schatz-Kammer Der Kaufmannschafft (1741–1743, 4 volumes and 1 supplement volume), stock exchange laws Corpus Juris Cambialis (Johann Gottlieb Siegels, 1742, 2 volumes) and the Historical-Political-Geographical Atlas of the Whole World (1744–1749, 13 volumes), published under the name of the Leipzig bookseller, Johann Samuel Heinsius the Elder.

Zedler died at the age of 45 in 1751, just a year after the conclusion of the alphabetic Universal-Lexicon. His name lives on with the colloquial name of the encyclopedia, which is known today as "the Zedler".

Johann Heinrich Zedler was born in 1706 in Breslau, the son of a shoemaker, and presumably did not have higher secondary education – if he attended school at all. He was an apprentice with the Breslau booksellers Brachvogel, then moved to the company of the Hamburg bookseller and publisher Theodor Christoph Felginer. In 1726 he moved to the Saxon town of Freiberg, and in September that year married Christiana Dorothea Richter (1695–1755), sister of publisher David Richter and daughter of a reputable merchant in the city, who was eleven years his elder. He used his wife's dowry to open a bookshop in Freiberg. Zedler only stayed in Freiberg for a short time since the mining town did not provide a sufficient market for books.

In 1727, Zedler and his wife moved to the university and trade fair city of Leipzig. That year his name appeared in a list of sixteen publishing booksellers in Leipzig. In September, Zedler announced his first published works after moving to Leipzig. The ad appeared just before the Leipzig Michaelmas Fair in October and was aimed at the many visitors to the city for this event.

Early in 1728 Zedler published a notice of "A New Enlarged and Revised Edition of All the German Journals and Works of the Blessed Luther". Unlike the previous work by theologian Johann Gottlieb Pfeiffer, Zedler's book did not follow a chronological sequence, but organized the material around themes. This was the first of seven volumes of work designed for high school use. The work was financed through Praenumeration, a common practice at the time. Interested parties would pay for two sections in advance at the Easter Fair in 1728, with a discount, and then receive delivery at the following Michaelmas Fair in early October. Zedler offered a particularly attractive price, making reprint by other booksellers unprofitable.

Since Zedler could not expect to raise enough funds for publication in this way, he also took a loan of 2,665 thalers from his brother-in-law David Richter. It is clear that this was a time of considerable uncertainty. Although Zedler had committed to publication on October 1728, as a precaution the year 1729 was printed on the title page. However, he met the deadline and fourteen days before the fair announced that the book was ready and no new subscribers to the Praenumeration plan would be accepted. Within a year Zedler had built a viable publishing business based on the success of the Luther series.