John Gill Commentary Zechariah 1:18

"And I lifted up mine eyes, and saw, and, behold, four horns." — Zechariah 1:18 (ASV)

Then I lifted up mine eyes To behold another vision which follows: and saw, and behold four horns; either iron ones, such as Zedekiah the son of Chenaanah made to push the Syrians with, (1 Kings 22:11) or horns of beasts, as the horns of unicorns, to which the horns of Joseph are compared, (Deuteronomy 33:17) and signify kingdoms or kings, and these very powerful and mighty; and so the Targum interprets them of "four kingdoms"; and which Kimchi and Abarbinel understand of the four monarchies, Babylonian, Persian, Grecian, and Roman; so ten horns, in (Daniel 7:24) (Revelation 17:12) design ten kings or kingdoms.

Unless rather, seeing these horns were such who had already distressed and scattered Judah, Israel, and Jerusalem; and two of the above monarchies were not yet in being, the Grecian and Roman, when this vision was seen; and one of those that were, were friends to the Jews, as the Persians; they may in general signify all the enemies of the Jews that were round about them, on the four corners of them; as the Syrians, Assyrians, and Babylonians, on the north; the Ammonites and Moabites on the east; the Edomites and Egyptians on the south; and the Philistines on the west; as Junius thinks.

Cocceius interprets them of four kings, Shalmaneser, Nebuchadnezzar, Xerxes, and Artaxerxes the first, called Longimanus; and may be applied to the antichristian states, Pagan and Papal, in the various parts of the world, called horns, (Daniel 7:24) (Revelation 12:3) (13:1).