The garments from Sonakshi's wardrobe will be available on SaltScout.com, an online platform for charity auctions and sales, from July 2.
Sonakshi is the second celebrity guest to join the initiative, which aims to benefit the planet and support the education and healthcare of the underprivileged through Being Human - The Salman Khan Foundation.
Alia said in a statement: "Through MiSu, we're trying to increase awareness around reusing and recycling, to divert clothing from landfills and help reduce waste.
"I'm grateful for Sona's generous support on the initiative. The response from friends and fans has been so encouraging and going forward we plan to introduce other celebrity wardrobes giving fans around the world a chance to be a part of the eco-movement."
Sonakshi said: "It is a lovely idea and I was only too happy to chip in with Alia and help do my bit. Each buyer gets a garment that has sentimental value."
'Mi Wardrobe is Su Wardrobe' is a closet sharing initiative conceptualised by Alia Bhatt.
The first two instalments saw Alia's wardrobe on sale, proceeds from which supported the Liter of Light program and The Corbett Foundation respectively.The third instalment featured actress Anushka Sharma's wardrobe, proceeds from which will support animal welfare.
( With inputs from IANS )