When a Jewish girl reaches the age of 12 years, which according to Judaism is the age of maturity, she becomes responsible for herself under Jewish law. At this point in her life she becomes Bat Mitzvah ("daughter of the commandment").
Before Bat Mitzvah, all responsibility for the girl's actions lies with the parents. After Bat Mitzvah, she is privileged to participate in all aspects of Jewish community life and bear her own responsibility in the areas of Jewish ritual law, tradition, and ethics.
In Orthodox Judaism, women are not considered obliged to obey the same laws as men, so they do not have similar ceremonies as the Bar Mitzvah of the boys.
In the Reform and Conservative Judaism there is no gender distinctions as far as the religious obligations. Today, non-orthodox Jews celebrate a girl's becoming Bat Mitzvah in the same way as a boy's becoming Bar Mitzvah.
Most Reform and Conservative synagogues have egalitarian participation in which women may read from the Torah and lead services. Conservative Judaism is pluralistic, and some synagogues are still concerned about the halakhic propriety of women reading the Torah portion to men.
The majority of Orthodox Judaism rejects the idea that a woman can read from the Torah or lead prayer services and has developed a less public way to mark this occasion. In some cases, Orthodox girls will lecture on a Jewish topic to mark their Bat Mitzvah.