Friedrichsdorf (German pronunciation: [ˈfʁiːdʁɪçsˌdɔʁf] ^ⓘ) is a town of the Hochtaunuskreis, some 20 km (12 mi) north of Frankfurt am Main in Hesse, Germany.

Friedrichsdorf is located in the Taunus area, ranking third among the Hochtaunuskreis boroughs after Bad Homburg vor der Höhe and Oberursel (Taunus). The municipal area includes, on the one hand, agricultural land such as that between Burgholzhausen and the edge of the Wetterau. On the other hand, there are vast woodlands on the crest of the Taunus, where the highest point in Friedrichsdorf's rural areas can be found: the Gickelsburg at 471 m above sea level. From the Taunus' heights, the river Erlenbach makes its way down and through town.

Friedrichsdorf borders in the north and east on the town of Rosbach (Wetteraukreis), in the south on the town of Bad Homburg, and in the west on the community of Wehrheim.

The town's founding in 1687 goes back to the persecution of the Huguenots in France, where millions of them fled their country. Part of this exodus was granted asylum by Landgrave Friedrich II with the words "Lieber will ich mein Silbergerät verkaufen, als diesen armen Leuten die Aufnahme versagen" ("I would rather sell my silverware than deny these poor people asylum."). The Huguenots then founded Friedrichsdorf, gratefully naming it after the Landgrave. They brought flannel and stockings with them from France, which spread quickly.

Later, Zwieback was produced in Friedrichsdorf, which is why Friedrichsdorf is known as the "Town of Zwieback". The zwieback factory "Emil Louis Pauly" became Milupa, still in business now as a baby food maker, and still headquartered in Friedrichsdorf. It is now owned by Numico, a Dutch company, and the production facilities have been moved abroad.

The town's most famous son was Johann Philipp Reis, a teacher at the Institut Garnier. He is the inventor of the electric transmission of speech, better known as the telephone and has been dedicated a museum. Friedrichsdorf's comprehensive school (Philipp-Reis-Schule) is also named after him.

In 1916, Dillingen, which had been founded only in 1804, was joined with Friedrichsdorf. Dillingen took its name from a village which had been forsaken in the Thirty Years' War, on the rural area of which Friedrichsdorf's Huguenots later settled. Paul Tirard reported that the town archives were kept in French up until 1871, but thenceforth in German. He also states that the names on grave stones were French up and till 1914 and that Protestant Sunday services were held locally up until the same date.

In July 1972 the communities of Friedrichsdorf, Seulberg, Köppern and Burgholzhausen merged to form the town of Friedrichsdorf/Taunus.