Davorin Trstenjak (8 November 1817 – 2 February 1890) was a Slovene writer, historian and Roman Catholic priest.
Trstenjak was born in the village of Kraljevci near Sveti Jurij ob Ščavnici, in what was then the Austrian Duchy of Styria (now in Slovenia). He attended the elementary school in his home village and later in Bad Radkersburg (Slovene: Radgona) where he met the philologist Peter Dajnko, with whom he established a close friendship. He studied at the lyceum in Maribor and later in Graz, where he became a supporter of the Illyrian movement, a Romantic nationalist cultural movement that spread from the neighbouring Croatia, and which advocated a cultural and linguistic unification of the South Slavic peoples.
After graduating from theology, he was ordained in 1844, then he served as a chaplain in the Lower Styrian villages in Slivnica pri Mariboru (1844–46), Ljutomer (1847), Hajdina (1848), and the town of Ptuj (1849–50). From 1850 until 1861, he was a chaplain and then a catechist in Maribor. From 1861 until 1868, he was the parish priest in Šentjur, then from 1868 until 1879 in Ponikva, and from 1879 until his death in Stari Trg near Slovenj Gradec.