Yahrzeit or Yohr Tzeit, means "Time (of) Year" in Yiddish. The word is also used by non-Yiddish-speaking Ashkenazi Jews, and refers to the annual anniversary of the day of death of a relative. Yahrzeit comes from the German word Jahreszeit (meaning "time of year"). The commemoration is known in Ladino as nohala.

It is a widely observed halakha (Jewish law), based on the Jewish tradition that mourners are required to commemorate the death of a relative. Mourners required to fulfill this observance are the children, siblings, spouses and parents of the deceased.

The date of the Yahrzeit is determined by the Hebrew calendar, and falls annually on the Hebrew date of the deceased relative's death.

The main halakhic obligation is to recite the mourner's version of the Kaddish prayer three times (evening, morning, and afternoon). (During the morning prayer service the mourner's Kaddish is recited at least four times.) Mourners also light a special candle which burns for 24 hours, called a "Yahrzeit candle".

In is customary to fast on the day of the Yahrzeit. While some Jews still do this, among many Orthodox Jews it has become customary to complete a tractate of Talmud or a volume of the Mishnah on the day prior to the Yahrzeit, in the honor of the deceased. A halakha requiring a siyum (celebratory meal), upon the completion of such a study, overrides the requirement to fast.