Can I marry my niece from a half-sister?

Question

My father married two women, Basically my half sister and I share same father (biological) but we have different mothers. Can I marry my half sister's daughter(my half niece) ?

Answer 1

You can not, your half-sister is your mahram, and so is her daughter.

حُرِّمَتْ عَلَيْكُمْ ... وَبَنَاتُ الْأُخْتِ

Prohibited to you [for marriage] are ... your sister's daughters ...

^{Quran 4:23}

From Tafsir Qurtubi:

والأخت ٱسم لكل أُنثى جاورتك في أصليْك أو في أحدهما

"Sister" is the name of every female who is your sibling, from both sides or just one.

Also see: IslamWeb and IslamQA