In Genesis 37:9, Joseph dreams:
"And he dreamed yet another dream, and told it his brethren, and said, Behold, I have dreamed a dream more; and, behold, the sun and the moon and the eleven stars made obeisance to me."
Joseph had eleven brothers, and he himself was the twelfth son of Jacob (Israel). So the eleven stars represent his eleven brothers, bowing to him in the dream. Joseph doesn’t include himself as one of the stars, he is the one being bowed to.
Sun = Jacob (his father, Israel)
Moon = Rachel (his mother; though she had already died, this may be symbolic)
Eleven stars = His brothers (the other sons of Jacob)
Later in the chapter, even Jacob understands the meaning of the dream: “Shall I and thy mother and thy brethren indeed come to bow down ourselves to thee to the earth?” (Genesis 37:10)
Joseph’s dream symbolically foretells the future bowing of his eleven brothers to him, fulfilled when he becomes ruler in Egypt. The "eleven stars" make sense because he is not included among those bowing in the vision. Later, this symbolism becomes deeply prophetic, forming the foundation of how the twelve tribes of Israel are seen, including in Revelation 12 where a similar image appears.