Are there many gods, or is there only one God?

The Bible says that even though many gods exist, there is only "one true God"...the Father. (John 17:3)

Anything that is worshiped can be termed a god. Satan is even called “The god of this world” (2 Corinthians 4:4). A person can even let his belly be a god. (Rom. 16:18; Php 3:18, 19) The Bible makes mention of many gods (Ps 86:8; 1Co 8:5, 6), but it shows that the gods of the nations are valueless gods. (Ps 96:5)

The Bible says that "there are those who are called “gods,” whether in heaven or on earth, just as there are many “gods” and many “lords” (1 Cor. 8:5). But the scripture goes on to say that "there is actually to us one God the Father". (1 Cor. 8:6)

People long ago realized this and exclaimed: “Jehovah is the true God! Jehovah is the true God!” (1 Kings 18:39)
 
And Jesus reaffirmed this by calling the "Father...the only true God." (John 17:1-3)
 
For more, see
God and gods - What is a god and who have been 'gods'?

Is There Only One True God?
 
WHO IS “the Only True God”?
 
Identifying the Only True God
 
“Those Who Are Called ‘Gods’”