Isaiah 45 is the forty-fifth chapter of the Book of Isaiah in the Hebrew Bible or the Old Testament of the Christian Bible. This book contains the prophecies attributed to the prophet Isaiah, and is one of the Books of the Prophets.

The original text was written in Hebrew language. Some early manuscripts containing the text of this chapter in Hebrew belong to the Masoretic Text tradition, which includes the Codex Cairensis (895), the Petersburg Codex of the Prophets (916), Aleppo Codex (10th century), and Codex Leningradensis (1008).

Fragments containing parts of this chapter were found among the Dead Sea Scrolls (3rd century BC or later):

There is also a translation into Koine Greek known as the Septuagint, made in the last few centuries BCE. Extant ancient manuscripts of the Septuagint version include Codex Vaticanus (B; ${\displaystyle {\mathfrak {G}}}$^B; 4th century), Codex Sinaiticus (S; BHK: ${\displaystyle {\mathfrak {G}}}$^S; 4th century), Codex Alexandrinus (A; ${\displaystyle {\mathfrak {G}}}$^A; 5th century) and Codex Marchalianus (Q; ${\displaystyle {\mathfrak {G}}}$^Q; 6th century).

This chapter is divided into 25 verses.

The parashah sections listed here are based on the Aleppo Codex. Isaiah 45 is a part of the Consolations (Isaiah 40–66). {P}: open parashah; {S}: closed parashah.

Thus saith the LORD to His anointed, to Cyrus, whose right hand I have holden, to subdue nations before him, and to loose the loins of kings; to open the doors before him, and that the gates may not be shut:

— Isaiah 45:1