Which king of Assyria captured Galilee and Naphtali in the days of King Pekah?

Answer: Tiglath-pileser

In Pekah's days Tiglath-pileser king of Assyria captured Gilead, Galilee and all Naphtali and took the people captive to Assyria.

“In the days of Pekah king of Israel, Tiglath-pileser king of Assyria came and captured Ijon, Abel-beth-maacah, Janoah, Kedesh, Hazor, Gilead, and Galilee, including all the land of Naphtali, and he took the people as captives to Assyria.”— 2 Kings 15:29 (BSB)