Her work contains only a few apparent allusions to the political disturbances of the time, which are so frequently reflected in the verse of her contemporary Alcaeus. Her themes are invariably personal—primarily concerned with her thiasos, the usual term (not found in Sappho's extant writings) for the female community, with a religious and educational background, that met under her leadership. Sappho herself attacks in her poems other thiasoi directed by other women.

The goal of the Sapphic thiasos is the education of young women, especially for marriage. Aphrodite is the group's tutelary divinity and inspiration. Sappho is the intimate and servant of the goddess and her intermediary with the girls. In the ode to Aphrodite, the poet invokes the goddess to appear, as she has in the past, and to be her ally in persuading a girl she desires to love her. Frequent images in Sappho's poetry include flowers, bright garlands, naturalistic outdoor scenes, altars smoking with incense, perfumed unguents to sprinkle on the body and bathe the hair—that is, all the elements of Aphrodite's rituals. In the thiasos the girls were educated and initiated into grace and elegance for seduction and love. Singing, dancing, and poetry played a central role in this educational process and other cultural occasions. As was true for other female communities, including the Spartan, and for the corresponding masculine institutions, the practice of homoeroticism within the thiasos played a role in the context of initiation and education. In Sappho's poetry love is passion, an inescapable power that moves at the will of the goddess; it is desire and sensual emotion; it is nostalgia and memory of affections that are now distant, but shared by the community of the thiasos. There is a personal poetic dimension, which is also collective because all the girls of the group recognize themselves in it. An important part of Sappho's poetic oeuvre is occupied by epithalamia (epithalamium), or nuptial songs.

It is not known how her poems were published and circulated in her own lifetime and for the following three or four centuries. In the era of Alexandrian scholarship (3rd and 2nd centuries BC), what survived of her work was collected and published in a standard edition of nine books of lyrical verse, divided according to metre. This edition did not endure beyond the early Middle Ages. By the 8th or 9th century AD Sappho was represented only by quotations in other authors. Only the ode to Aphrodite, 28 lines long, is complete. The next longest fragment is 16 lines long. Since 1898 these fragments have been greatly increased by papyrus finds, though, in the opinion of some scholars, nothing equal in quality to the two longer poems.