[Avodah] Is there a mitzvah to honor step-parents?

[Professor L. Levine]

>From today's OU Kosher Halacha Yomis.

    Q. Is there a mitzvah to honor step-parents?

    A. There is a Torah obligation to honor a step-mother or a
    step-father so long as one's father or mother is still alive. Once
    the parent passes away, there is no further obligation to honor
    the step-parent. However, the Gemara (Kesubos 103a) relates that
    Rebbi Yehuda HaNasi instructed his children before his passing
    to continue to show honor to their step-mother, and this is the
    accepted practice of all G-d fearing individuals even though it is
    not a formal obligation (Aruch Hashulchan YD 240:43).

    The Birkei Yosef (YD 240:16) writes that one is obligated
    to show honor to their step-mother even if their birth mother
    objects. Honoring their step-mother is a means of honoring their
    father, and the birth mother's objections do not remove this
    obligation. However, Halachos Ketanos (1:28) writes that if there
    is a question of who should be honored first (e.g., one's mother and
    step-mother both ask for a drink of water), one is obligated to honor
    one's mother first. Though they are both Torah obligations, the honor
    that is due to a parent is greater than that due to a step-parent.