Simeon Stylites the Younger, also known as Simeon of the Admirable Mountain (Greek: Συμεὼν ὁ νεώτερος ὁ στυλίτης, Arabic: مار سمعان العمودي الأصغر mār semʻān l-ʻamūdī l-asghar; 521 – 596/597), is a saint in the Catholic Church and Eastern Orthodox Church.

Stylites were solitaries who, taking up their abode upon the tops of a pillar (stylos), chose to spend their days amid the restraints thus entailed and in the exercise of other forms of asceticism.

He attached himself to a community of ascetics living within the mandra or enclosure of another pillar-hermit, named John, who acted as their spiritual director.

In a letter to Thomas, guardian of the True Cross at Jerusalem, Simeon states that he was living upon a pillar when he lost his first teeth.

Towards the close of his life the saint occupied a column upon a mountainside near Antioch called the "Hill of Wonders" (due to his miracles), also known as the "Wondrous Mountain" or the "Admirable Mountain" (Classical Syriac: ܛܘܪܐ ܕܬܕܡܪܬܐ, Ṭūrā d-ṯeḏmūrtā; Greek: Θαυματόν Ὄρος, Thaumaton Oros); this mountain is known today in Turkish as Samandağı (modern Arabic name: جبل سمعان, Jabal Simʻān or جبل ليلون, Jabal Laylūn) and is located near the town of Samandağ, Turkey.

The Wellcome Collection has a tempera on wood painting by an unknown artist of Saint Simeon Stylites the Younger.