Snotra is the goddess of wisdom, self-control, knowledge and foresight in Norse mythology. She is one of the five servants of Frigg.
According to Snorri Sturluson's Edda, Snotra is the thirteenth of the Aesir. She is full of wisdom and grace, and from her name Snotr means a wise man or woman.
She is not mentioned in either the Poetic Edda or the Scaldic poetry, nor in any other Nordic or Germanic source.
Because of this lack of evidence it has been suggested, for example by Rudolf Simek in his Dictionary of Norse Mythology, that Snotra was an invention of Snorri Sturluson.
Although this was undoubtedly possible, it is not clear why Snorri would have invented a goddess out of thin air, especially since Snotra is the thirteenth on his list. One could think that he would have been satisfied with twelve Aesir to match the twelve Aesir he counts in the Nordic pantheon.
A possible explanation is that Snotra would have been an alternative name for another goddess, perhaps Frigg, and that Snorri would thought her to be a different goddess. Having nothing else to say about it, Snorri would then have been content to inform his readers that Snotra is "wise and gracious", based on her name alone.
It is also conceivable that Snorri had access to an authentic, albeit limited, oral tradition that would not have been transmitted to us by any other source.