While not technically a "sidekick" in the traditional sense, Miles acts as a partner and successor to Peter Parker. He is a Spider-Man in his own right, but shares the mantle and learns from Peter's experience.
Here are some other notable Spider-Man sidekicks:
* Hobie Brown (The Prowler): A young, struggling inventor, Hobie briefly became Spider-Man's ally but eventually went down a darker path.
* The Human Torch (Johnny Storm): Though not technically a sidekick, Johnny Storm and Spider-Man were close allies and often teamed up in the early days of the Fantastic Four.
* The Black Cat (Felicia Hardy): While sometimes a villain, Felicia Hardy has often been Spider-Man's ally, lover, and friend.
So, depending on what you mean by "sidekick," the answer could be Miles Morales, Hobie Brown, or even the Black Cat.