Illuminationism (Persian حكمت اشراق hekmat-e eshrāq, Arabic: حكمة الإشراق ḥikmat al-ishrāq, both meaning "Wisdom of the Rising Light"), also known as Ishrāqiyyun or simply Ishrāqi (Persian اشراق, Arabic: الإشراق, lit. "Rising", as in "Shining of the Rising Sun") is a philosophical and mystical school of thought introduced by Shahab al-Din Suhrawardi (honorific: Shaikh al-ʿIshraq or Shaikh-i-Ishraq, both meaning "Master of Illumination") in the twelfth century, established with his Kitab Hikmat al-Ishraq (lit: "Book of the Wisdom of Illumination"), a fundamental text finished in 1186. Written with influence from Avicennism, Peripateticism, and Neoplatonism, the philosophy is nevertheless distinct as a novel and holistic addition to the history of Islamic philosophy.

While the Ilkhanate-Mongol Siege of Baghdad and the destruction of the House of Wisdom (Arabic: بيت الحكمة, romanized: Bayt al-Ḥikmah) effectively ended the Islamic Golden Age in 1258, it also paved the way for novel philosophical invention. Such an example is the work of philosopher Abu'l-Barakāt al-Baghdādī, specifically his Kitāb al-Muʿtabar ("The Book of What Has Been Established by Personal Reflection"); the book's challenges to the Aristotelian norm in Islamic philosophy along with al-Baghdādī's emphasis on "evident self-reflection" and his revival of the Platonic use of light as a metaphor for phenomena like inspiration all influenced the philosophy of Suhrawardi. The philosopher and logician Zayn al-Din Omar Savaji further inspired Suhrawardi with his foundational works on mathematics and his creativity in reconstructing the Organon; Savaji's two-part logic based on "expository propositions" (al-aqwāl al-šāreḥa) and "proof theory" (ḥojaj) served as the precursory model for Suhrawardi's own "Rules of Thought" (al-Żawābeṭ al-fekr). Among the three Islamic philosophers mentioned in Suhrawardi's work, al-Baghdādī and Savaji are two of them.

Upon finishing his Kitab Hikmat al-Ishraq (lit: "Book of the Wisdom of Illumination"), the Persian philosopher Shahab al-Din Suhrawardi founded Illuminationism in 1186. The Persian and Islamic school draws on ancient Iranian philosophical disciplines, Avicennism (Ibn Sina's early Islamic philosophy), Neoplatonic thought (modified by Ibn Sina), and the original ideas of Suhrawardi.

In his Philosophy of Illumination, Suhrawardi argued that light operates at all levels and hierarchies of reality (PI, 97.7–98.11). Light produces immaterial and substantial lights, including immaterial intellects (angels), human and animal souls, and even 'dusky substances', such as bodies.

Suhrawardi's metaphysics is based on two principles. The first is a form of the principle of sufficient reason. The second principle is Aristotle's principle that an actual infinity is impossible.

The essential meaning of ishrāq (Persian اشراق, Arabic: الإشراق) is "rising", specifically referring to the sunrise, though "illumination" is the more common translation. It has used both Arabic and Persian philosophical texts as means to signify the relation between the "apprehending subject" (al-mawżuʿ al-modrek) and the "apprehensible object" (al-modrak); beyond philosophical discourse, it is a term used in common discussion. Suhrawardi utilized the ordinariness of the word in order to encompass the all that is mystical along with an array of different kinds of knowledge, including elhām, meaning personal inspiration.

Suhrawardi tried to present a new perspective on questions like those of existence. He not only caused peripatetic philosophers to confront such new questions, but also gave new life to the body of philosophy after Avicenna. According to John Walbridge, Suhrawardi's critiques of Peripatetic philosophy could be counted as an important turning point for his successors. Although Suhravardi was first a pioneer of Peripatetic philosophy, he later became a Platonist following a mystical experience. He is also counted as one who revived the ancient wisdom in Persia by his philosophy of illumination. His followers, such as Shahrzouri and Qutb al-Din al-Shirazi tried to continue the way of their teacher. Suhrewardi makes a distinction between two approaches in the philosophy of illumination: one approach is discursive and another is intuitive.

Illuminationist thinkers in the School of Isfahan played a significant role in revitalizing academic life in the Safavid Empire under Shah Abbas I (1588–1629). Avicennan thought continued to inform philosophy during the reign of the Safavid Empire. Illuminationism was taught in Safavid Madrasas (places of study) established by pious shahs.