Writers Of Proverbs
Proverbs 1:1 (NIV)

1 The proverbs of Solomon
son of David, king of Israel:

Proverbs Club Commentary

Both Solomon and his father, David, were kings of Israel.
Proverbs 1-29 are attributed to Solomon, son of David.
Proverbs 30 is attributed to Agur, son of Jakeh.
Proverbs 31 is attributed to King Lemuel, from his mother.