Is Goku the First Super Saiyan? As stated in the question, is Goku the first Super Saiyan?  If not, who was the first Super Saiyan? Was it:


Goku  
Broly  
Bardock (according to the Episode of Bardock)
Someone else
Historically, Probably NO.

Original Super Saiyan was originally thought to be a legend, until Goku first transformed during his fight with Frieza. In a filler scene in episode 66 of DBZ, the first appearance of the Original Super Saiyan was shown, it looks like a Great Ape with yellowish colored fur. Apparently Super Saiyan was not in Great Ape form, unless it's a Golden Great Ape, it was made up by Vegeta's imagination.



Talking about Bardock, he was suspected as the first Super Saiyan, there is no official information to prove he is the first ever Saiyan to transform into a Super Saiyan. At the end of Episode of Bardock, it is revealed that Chilled's knowledge about Super Saiyans was passed to his descendants. It is not confirmed yet that Akira Toriyama wants Bardock to be the first Super Saiyan. 

But until now, Bardock was the first Super Saiyan in the series with a known name and appearance.