In the 1940s, Mirza Muhammad Qazvini declared that we can “confidently add the great philosopher Nasir Khusraw” to the list of greatest Persian poets since the coming of Islam: Firdawsi, Khayyam, Anvari, Rumi, Sa’di, Hafiz. One of the earliest Persian poets with a sizeable Divan still extant (numbering 10,600 verses), Nasir Khusraw is also noteworthy as perhaps the first to dedicate himself to specifically religious poetry. But more than such a historical marker, the strength of his verses is apparent in their having become an integral part of the language: many of his phrases have become proverbs still repeated today. This paper will analyse the significant features of his poetry and discuss some of the literary influences on his Divan, tracing his use of metre and rhyme back to his forebears in Khurasan. It will also discuss the impact of his verse, with specific reference to the later Persian tadhkira tradition down to early modern times, and will conclude with an overall assessment of this Ismaili sage's service to Persian language and literature.