Effendi, Effendy or Efendi (Greek:αφέντης IPA: [aˈfendis]; Ottoman Turkish language: افندي Efendi, Arabic: أفندي Sindhi: 'آفندي 'Afandī; Persian: آفندی ‎‎, Urdu: آفندی ‎) is a title of nobility meaning a Lord or Master.

It is a title of respect or courtesy, equivalent to the English Sir, which was used in the Ottoman Empire. It follows the personal name, when it is used, and is generally given to members of the learned professions and to government officials who have high ranks, such as bey or pasha. It may also indicate a definite office, as hekim efendi, chief physician to the sultan. The possessive form efendim (my master) is used by servants, in formal discourse, when answering the telephone, and can substitute for "excuse me" in some situations (e.g. asking someone to repeat something) .