Matthew 12:46 states, "While he [Jesus] was still speaking to the people, behold, his mother and his brothers stood outside, asking to speak to him." Luke 8:19 adds, "Then his mother and his brothers came to him, but they could not reach him because of the crowd."
Matthew 13:55 says, "Is not this the carpenter's son? Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas?" This James was the author of the book of James in the New Testament. Galatians 1:19 states, "James the Lord's brother." Judas (also known as Jude) was the author of the book of Jude in the New Testament.
John 7:1-10 says that Jesus' brothers attended the Jewish festival while Jesus stayed behind.
A look at Matthew 13:56 would indicated that Jesus had more than one sister: "And are not all his sisters with us?"