Nethaniah in the Bible

1. Father of Ishmael

2 Kings 25:23 And when all the captains of the armies, they and their men, heard that the king of Babylon had made Gedaliah governor, there came to Gedaliah to Mizpah, even Ishmael the son of Nethaniah, and Johanan the son of Careah, and Seraiah the son of Tanhumeth the Netophathite, and Jaazaniah the son of a Maachathite, they and their men.
2 Kings 25:25 But it came to pass in the seventh month, that Ishmael the son of Nethaniah, the son of Elishama, of the seed royal, came, and ten men with him, and smote Gedaliah, that he died, and the Jews and the Chaldees that were with him at Mizpah.
Jeremiah 40:8 Then they came to Gedaliah to Mizpah, even Ishmael the son of Nethaniah, and Johanan and Jonathan the sons of Kareah, and Seraiah the son of Tanhumeth, and the sons of Ephai the Netophathite, and Jezaniah the son of a Maachathite, they and their men.
Jeremiah 40:14-15 And said unto him, Dost thou certainly know that Baalis the king of the Ammonites hath sent Ishmael the son of Nethaniah to slay thee? But Gedaliah the son of Ahikam believed them not. 15 Then Johanan the son of Kareah spake to Gedaliah in Mizpah secretly, saying, Let me go, I pray thee, and I will slay Ishmael the son of Nethaniah, and no man shall know it: wherefore should he slay thee, that all the Jews which are gathered unto thee should be scattered, and the remnant in Judah perish?
Jeremiah 41:1-2 Now it came to pass in the seventh month, that Ishmael the son of Nethaniah the son of Elishama, of the seed royal, and the princes of the king, even ten men with him, came unto Gedaliah the son of Ahikam to Mizpah; and there they did eat bread together in Mizpah. 2 Then arose Ishmael the son of Nethaniah, and the ten men that were with him, and smote Gedaliah the son of Ahikam the son of Shaphan with the sword, and slew him, whom the king of Babylon had made governor over the land.
Jeremiah 41:6-7 And Ishmael the son of Nethaniah went forth from Mizpah to meet them, weeping all along as he went: and it came to pass, as he met them, he said unto them, Come to Gedaliah the son of Ahikam. 7 And it was so, when they came into the midst of the city, that Ishmael the son of Nethaniah slew them, and cast them into the midst of the pit, he, and the men that were with him.
Jeremiah 41:9-12 Now the pit wherein Ishmael had cast all the dead bodies of the men, whom he had slain because of Gedaliah, was it which Asa the king had made for fear of Baasha king of Israel: and Ishmael the son of Nethaniah filled it with them that were slain. 10 Then Ishmael carried away captive all the residue of the people that were in Mizpah, even the king's daughters, and all the people that remained in Mizpah, whom Nebuzaradan the captain of the guard had committed to Gedaliah the son of Ahikam: and Ishmael the son of Nethaniah carried them away captive, and departed to go over to the Ammonites. 11 But when Johanan the son of Kareah, and all the captains of the forces that were with him, heard of all the evil that Ishmael the son of Nethaniah had done, 12 Then they took all the men, and went to fight with Ishmael the son of Nethaniah, and found him by the great waters that are in Gibeon.

⇒Bible Encyclopedia for NETHANIAH.

2. A singer, and chief of the temple musicians

1 Chronicles 25:2 Of the sons of Asaph; Zaccur, and Joseph, and Nethaniah, and Asarelah, the sons of Asaph under the hands of Asaph, which prophesied according to the order of the king.
1 Chronicles 25:12 The fifth to Nethaniah, he, his sons, and his brethren, were twelve:

3. A Levite appointed by Jehoshaphat to accompany the princes who were to teach the law in Judah

2 Chronicles 17:8 And with them he sent Levites, even Shemaiah, and Nethaniah, and Zebadiah, and Asahel, and Shemiramoth, and Jehonathan, and Adonijah, and Tobijah, and Tobadonijah, Levites; and with them Elishama and Jehoram, priests.

4. Father of Jehudi

Jeremiah 36:14 Therefore all the princes sent Jehudi the son of Nethaniah, the son of Shelemiah, the son of Cushi, unto Baruch, saying, Take in thine hand the roll wherein thou hast read in the ears of the people, and come. So Baruch the son of Neriah took the roll in his hand, and came unto them.