The move applies to single and twin packs of the product. Single garlic baguettes are M&S Food’s top seller in the category with some 4.3 million sold a year.
Its garlic baguettes are now packed in FSC-certified paper packaging, which can be recycled in domestic recycling streams.
The FSC number indicates the packaging is produced by flexible packaging specialist Interflex Group, which has UK operations in Sunderland and Dalkeith.
The retailer said the switch would remove 5.5 million units of plastic a year from its food business.
M&S Food head of sustainability Lucinda Langton commented: “We know our customers rank packaging as a top priority and M&S is committed to reducing plastic packaging as a key part of our Plan A roadmap to Net Zero.
“It's a good step forward to remove 5.5 million units from our supply chain and we continue to work with our suppliers to find innovative new materials, processes, and equipment so we can make change at scale.
“These changes mean our customers can trust that the M&S quality products they love are made, sourced, and packaged with care.”
M&S also announced that it had achieved its target to remove 75 million units of plastic during 2023-2024 four months earlier than envisaged.
The £13bn turnover group’s Plan A roadmap to net zero includes a commitment to remove one billion plastic units by 2027.
The retailer said its new garlic bread packaging marked a first in UK retail.
Earlier this year M&S rolled out paper fibre coffee cups and lids at all its cafes.