Jesus' apostles are listed at five places in the Bible. The listings are slightly different, and here is how they can be reconciled: (The persons listed in the same row are the same.)

Mat 10:2-4	Mark 3:16-19	Luk 6:14-16	John 1:40-45	Act 1:13
Simon, who is called Peter	Simon he surnamed Peter	Simon, (whom he also named Peter,)	Simon the son of Jona: thou shalt be called Cephas	Peter
Andrew his brother	Andrew	Andrew his brother	Andrew, Simon Peter's brother	Andrew
James the son of Zebedee	James the son of Zebedee	James		James
John his brother	John the brother of James; and he surnamed them Boanerges	John		John
Philip	Philip	Philip	Philip	Philip
Bartholomew	Bartholomew	Bartholomew		Bartholomew
Thomas	Thomas	Thomas		Thomas
Matthew the publican	Matthew	Matthew		Matthew
James the son of Alphaeus	James the son of Alphaeus	James the son of Alphaeus		James the son of Alphaeus
Lebbaeus, whose surname was Thaddaeus	Thaddaeus	Judas the brother of James		Judas the brother of James
Simon the Canaanite	Simon the Canaanite	Simon called Zelotes		Simon Zelotes
Judas Iscariot	Judas Iscariot	Judas Iscariot
			Nathanael

Some people identify Nathanael with Bartholomew. The basis of their reasoning is that Nathanael occurs only in the Gospel of John while Bartholomew is never mentioned in that book. Since there is otherwise no scriptural evidence of them being the same person, they are listed separately here.

In Acts 1:26 the remaining 11 apostles selected Matthias as the 12th apostle in place of Judas Iscariot.