This essay analyses the work of Sor Juana Inés de la Cruz (1651-1695) in terms of its disruption of the colonial and patriarchal structures of the society of New Spain (as Mexico was then known) in which she lived. It begins with an analysis of her Reply to Sister Philotea (dated March 1, 1691) in which she alludes to her love of learning as well as her rejection of the notion that women have less right to knowledge than men, passes to a discussion of her famous “Philosophical Satire” in which she berated sexual injustice: “You foolish and unreasoning men/ who cast all blame on women,/ not seeing you yourselves are causes/ of the same fault you accuse.” The issue of the connection between Sor Juana’s poems which owe their very existence to the patronage system in which she operated (a poem celebrating the Viceroy of Mexico’s birthday, that of his wife, as well as the baptism of their son) and her so-called “personal lyrics” is discussed. The compositional rhetoric of the poems that have endeared Sor Juana to later (often feminist) audiences – sonnets such as “This afternoon when I spake with thee beloved…” and “Tarry, shadow of my scornful treasure…”) – is analysed in terms of the reality-appearance trope which underpinned so much Renaissance literature. The essay concludes with an analysis of her long poem, First Dream, and her verse plays such as Divine Narcissus.