The Church does not teach that Mary will have a second coming as Jesus does. Here it’s probably useful to distinguish between “second coming” and “apparition.” When we talk about the second coming of Jesus, we’re referencing the belief that Christ will come again at the end of time. As the Catechism states, “When he comes at the end of time to judge the living and the dead, the glorious Christ will reveal the secret disposition of hearts and will render to each man according to his works and according to his acceptance or refusal of grace. “(CCC 682) Thus, Christ’s second coming is connected with the Last Judgment and the end of time.
That said, it has long been believed by Catholics that Mary can and does appear on earth for the purpose of exhorting us to pray, repent, and grow closer to God. There have been countless Marian apparitions reported over the centuries, many of which have been investigated by the Church. Of these, a small number have been pronounced “worthy of belief” (note that the Church does not make a definitive pronouncement on whether or not the apparition is real). Even those judged to be “worthy of belief” are not a required part of a Catholic belief system; they are what is considered “private revelation,” thus Catholics are free to choose whether or not to incorporate them into their spirituality. Obviously, though, these apparitions and their messages of prayer and repentance do strike a chord with many Catholics. In a way, one could say that those who find meaning in the Marian apparitions may do so in part because they function as reminders to follow Jesus and remain open to the grace of God, thus preparing us for Judgment Day.