Is it shirk if a Muslim asks Maryam, the mother of Isa, for intercession?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

We have already clarified in Fatwa 4413 what types of intercession Islam permits.

Shaykh Ibn 'Uthaymeen said about asking intercession from the Prophet, sallallaahu 'alayhi wa sallam, after his death: "It is not permissible. This is forbidden, and it may even be an act of polytheism, because it is considered as supplicating and calling upon the Prophet . Instead of saying: 'I ask you, O Messenger of Allah, to intercede for me,' one must say: 'O Allah! Make Your Messenger intercede for me,' so that the supplication is directed to Allah Almighty, not to the Prophet .

The Prophet cannot intercede for you now. Even on the Day of Resurrection, he cannot intercede for anyone except with Allah's permission. So, this word is forbidden, and it may even be considered as associating others with Allah Almighty." [End of quote] Excerpted from the Fataawa of "Liqaa' Al-Baab Al-Maftouh".

Moreover, intercession belongs entirely to Allah Almighty. He Almighty permits whomever He wishes to intercede, if He wishes; Allah Almighty Says (what means): {Say, "To Allah belongs [the right to allow] intercession entirely. To Him belongs the dominion of the heavens and the earth. Then to Him you will be."}َ[Quran 39:44]

Thus, intercession is only asked from Allah Alone. It is not asked from a Messenger, or an angel, nor from righteous people.

Allah Knows best.