Betty Rubble is the young, relatively serene wife of Barney Rubble and best friend of next door neighbors Wilma and Fred Flintstone. Though no age is ever given, all four of them appear to be somewhere in their late twenties in the original television series, adults but still a little unseasoned by life and occasionally prone to daydreams, fan crushes on popular movie stars, and youthful misadventures.

The stablest and most sensible member of the four, Betty has played sounding board and voice of reason to each of the other three in numerous episodes. She remains a calming influence on the more emotional Wilma, often leading her to look past the outrage of the moment and to keep a reasonable sense of perspective about the daily frustrations of life, and she acts as both moral center for Barney and as a stabilizing counterinfluence against Fred's ability to play off Barney's gullibility and natural sweet-tempered conformity. More than once, Betty has been able to convince Fred to recognize his own culpability in one of his zany schemes when he would listen to no one else.

For all her old-fashioned wisdom and serenity, Betty is just as prone as anyone else her age to losing her temper, jumping to conclusions, and the occasional pang of jealousy that a young wife or husband might experience once in a while. Wilma and she often tease their husbands whenever Fred and Barney become disastrously cocky or recklessly naive (a fairly common occurence in a domestic sitcom such as The Flintstones).

In the original series continuity, Betty Jean McBricker and her best friend Wilma Slaghoople met their future husbands while working at a ritzy motel during one of their first summers after graduating from high school. From the very beginning, Betty found herself attracted only to Barney Rubble. In later continuities, the four of them have known each other since children. The Flintstones series have never really attempted to follow a single continuity, so both origins are probably true.

During the original television series run, Betty and Barney adopted Bamm Bamm, the world's strongest toddler. In sequel television series, Betty enters middle age (looking as youthful as ever) as son Bamm Bamm marries Pebbles Flintstone and, in one continuity, may have become a grandmother.

Like all the "cave people" of The Flintstones series, Betty easily performs feats of strength that are superhuman by modern standards, including punching out dinosaurs, and would appear to have a low level of invulnerability compared to a modern human being. (This greater strength and toughness has been vaguely alluded to the few times that the Rubbles and Flintstones have travelled into the future to the modern day or even past that to the retrofuturistic days of the Jetsons).