TP Group will deliver 750 multi-purpose oxygen generators under the £1m order.
The equipment is expected to be delivered to the Royal Navy during the fourth quarter of the year.
The company already supplies its combined oxygen generating system (COGS) to the MoD.
TP Group CEO Phil Cartmell said: “We are very pleased to see a further significant order materialise from our long-standing framework agreement with the MoD.
“This latest drawdown highlights the enduring value of these arrangements and further illustrates how the group provides ancillary solutions alongside major systems orders, providing an all-round service to our key customers.”
The latest order was awarded under an existing £22m framework contract signed between TP Group and the MoD in 2017.
The framework contract pertains to the management of equipment availability and the provision of spares for air purification systems.
It involves the delivery of eight COGS systems and ancillary items to upgrade Royal Navy submarines.
In February this year, the firm won a contract from the MoD to supply Extendair lithium hydroxide curtains for managing carbon dioxide contamination on-board submarines.
TP Group was also awarded a contract in May last year to deliver submarine atmosphere equipment for Royal Navy submarines.