This year, around 6,400 UK sailors, marines, soldiers, airmen and airwomen will be deployed on operations, including in Scotland.
In Europe, around 100 soldiers from 4 Scots and 4 Rifles will be in Ukraine over the festive period, providing training to Ukrainian Forces.
Elsewhere, soldiers from 2 Scots who are usually based in Penicuik, Midlothian, are currently deployed as part of the Nato training mentoring mission in Afghanistan, helping to maintain an uneasy peace.
Sergeant Regi Miller, of 2nd Battalion The Royal Regiment of Scotland, said: "On behalf of everyone in 2nd Battalion The Royal Regiment of Scotland over here in Kabul, Afghanistan, we'd like to wish you a Merry Christmas and a Happy New Year."
In total 11 Royal Navy vessels will be deployed overseas this Christmas, including those with links to Scotland.
Type 23 frigate HMS Montrose will be joining a further five ships in the Gulf region to provide protection to vital international shipping lanes in the Straits of Hormuz.
While Offshore Patrol Vessel HMS Forth will be in the Falkland Islands following a series of patrols in the South Atlantic.
The UK's Quick Reaction Alert Squadrons will be on duty at RAF Lossiemouth while the Submarine Service will also be at work over the Christmas period continuing to support the Continuous At Sea Deterrent.
In the run-up to Christmas sailors from HMS Neptune and Royal Marines from 43 Commando delivered Christmas trees to local communities around HMNB Clyde.
Commodore James Perks CBE, of the Submarine Service, said: "2020 has been a year like no other in recent times and I am immensely proud of the way that the Submarine Service has responded to the Covid-19 pandemic.
"Both service and civilian staff as well as our families and loved ones have all risen to the challenges that this year has brought."
Scottish Secretary Alister Jack praised military personnel for their work.
He said: "I am incredibly proud of the contribution that our brave servicemen and servicewomen from across Scotland have made this year in such challenging circumstances.
"I particularly commend them for their efforts here in Scotland through the pandemic, as well as the dedication and sacrifices many of them will be making at this time of year, away from loved ones, in order to keep us all safe.
"I wish them a very happy Christmas and New Year."Defence Minister Baroness Goldie said: "Our Armed Forces personnel have played a crucial role in the fight against the virus, in addition to the role they play in keeping us safe from other threats, at home and abroad.
"This Christmas thousands of personnel will be deployed in the UK and across the world, away from their families and the comforts of home.
"I would like to give my heartfelt thanks to the personnel and their families who are making such a great sacrifice so that we can enjoy our Christmases peacefully and safely."