The word ἀρχιερεύς is used 122 times in the NT in both singular and plural forms. In the Gospels and Acts of the Apostles, the word usually refers to the “High Priest” as the religious and civil leader of the Jewish nation. In the Epistle to the Hebrews, of its 17 occurrences, ἀρχιερεύς is 10 times explicitly or implicitly identified to Jesus Christ, as “High Priest”. Obviously, this identification raises questions about the role and functions of the “High Priest” in the OT. In the MT, the title hakkōhén haggādôl (הַכֹּהֵן הַגָּדוֹל) is used only 20 times to designate the Aaronic “High Priest”. The translators of the LXX have rendered it in Greek each time word for word: ὁ ἱερεὺς ὁ μέγας. In the books of the Maccabees, written during the two centuries before Jesus, ἀρχιερεύς is used to describe someone who were cumulating the functions of “High Priest”, military leader and ethnarch of the Jewish nation. In order to better understand the meaning of the word ἀρχιερεύς, the article addresses the following three points: 1) the vocabulary of the “High Priest” in the OT; 2) the role of the “High Priest” during the Second Temple period (516 BCE-70 CE); 3) the expectation of a “High Priest” of the messianic times.