This may seem obvious but is it? The Power Rangers are generally thought of as a Japanese super-hero series that was modified for an American audience. Yet, when people talk about their favorite superhero series or superhero characters, the Power Rangers never get brought up. Despite it being a huge franchise still.
It also qualifies as a martial arts series, for obvious reasons, but it’s so far away from being something akin to Kung Fu the television series, or Into the Badlands. It seems to not have the same distinction as those types of shows either.
Then there’s the obvious category it could fall under, the kaiju monster genre. Even in that genre though it doesn’t seem to be as accepted as something like the Ultra Series or the obvious, Godzilla franchise.
It’s mostly just labeled a “kids show” but a more accurate reason is, at least from a western perspective, that it takes too many elements of too many different genres and integrates them to be fully seen as only one thing. It’s equal parts kaiju, martial arts, and superhero. Yet, it’s also predominantly science fiction.
Think about it; it’s a television show about aliens that use advanced technology to try and conquer the world. Their only opposition is another alien being that outfits a group of people to fight back using equally as advanced technology in a long-standing war between good and evil. Oh, and they also go to outer space, alternate realities, the future, the past, and different timelines throughout the series’ run. All of that stuff is literally found in every science fiction show worth watching.
Du to it being such a hodgepodge of different genres, it feels right to just call the Power Rangers what it is; a science fiction series.