Tranquillinus can refer to:

• Tranquillinus, bishop of Tarragona (6th century).
• Saint Tranquillinus, father of Saints Mark and Marcellian (3rd century)

• Bishop Milner School
• Bishop Moore Vidyapith
• Bishop Moore Vidyapith Cherthala
• Bishop Moore Vidyapith (disambiguation)
• Bishop Moore Vidyapith, Kayamkulam
• Bishop Moore Vidyapith Kayamkulam
• Bishop moore vidyapith kayamkulam
• Bishop Morrow School
• Bishop Municipal Airport
• Bishop National Bank of Hawaii
• Bishop Nehru
• Bishop Nevins
• Bishop Nevins Academy
• Bishop Niceta of Remesiana
• Bishop Nicolson
• Bishop Nobis
• Bishop O'Connell High School
• Bishop of Aba
• Bishop of Abakaliki
• Bishop of Abancay
• Bishop of Abengourou
• Bishop of Abeokuta
• Bishop of Abidjan
• Bishop of Abomey
• Bishop of Abuja