Anyone know what Army Regulation (or any branch) that allows a higher-ranking officer to call a lower-ranking officers by their first name?

Strange question. First, not everything is in a regulation, although not for lack of effort on the Army's part. In the military and in civilian police departments, it is tradition for the boss to call the subordinate by first name. If your boss is using your first name, that's a good thing when done privately. Whenever I was unhappy with someone or had a total dud under me I called them by their rank, even in private. RHIP.

As for any reg allowingcommanding officers calling junior officers by theirfirst name, none that I know of. Often, a CO will use a junior officer's or an NCO by their first name in private. But all COs must exhit proffessionalism at all times..

You don't need a regulation to use good old fashioned professionalism and leadership skills.

Up front I'll say that for about 4 years I was airborne and worked with Special Forces a lot. Then for about 20 years a was an aviator and worked with aviators a lot (duh). While in an airborne unit I was a Lieutenant and only other Lieutenants called each other by their first name. My CO in the 82nd always called us Lieutenant followed by our last name. (My battalion commander did not know I existed until I made a big mistake, but that's another story.) The NCOs and men called us Lieutenant or Sir.

When I worked with Special Forces, while I was still a Lieutenant, after the initial getting to know you period, except for Sergeants (E5), they began calling me by my first name, which if you worked with SF in the 80s, was the normal thing. I considered it a compliment, that I was in with the guys. All of the team members used first names within the team with one exception. The Team Commander was usually addressed by a title of endearment such as, Cap, Skip, Boss, Jefe, etc. They were all a little wild and a little crazy, but they were professionals all the way.

After flight school I worked in 6th Cavalry Brigade HQ. As captains we were the low men on the totem pole. We called each other by our first names. My boss, a major, and his boss, a LTC, would sometimes call me by my first name and sometimes call me by my last name and sometimes call me Captain Arnold. (I think it had to do with their mood and my performance.) Warrant Officers in the HQ were treated the same as the captains and were called by their first name.

As an instructor at The US Army Aviation School we were on a first name basis. Warrant Officers were treated the same as the Captains at the school and were called by their first name. Field Grade officers were called Sir, but they called us by our first name.

As a Test Project Officer/Test Pilot for the US Army Aviation Board, like the school, we were mostly Captains and civilians and we were on a first name basis. Again, Field Grade officers were called Sir, but they called us by our first name.

In the 211 Aviation Group (Brigade size HQ) and in the 1/211th Avn. Bn. (AH-64) (which are UTARNG units) generally, WO1 thru Captain were on a first name basis. For me personally, W3, W4, and later W5 were on a first name basis with me when I was a Major. I was fine with that. The Warrant Officers were smart enough to know when not to use a senior officer's first name.

So, bottom line at the bottom, it all depends on the type of unit, the men and women you are working with, and you as an individual. (Sorry that took so long.)

RHIP

Thank you CSM.

Don't ever watch mash?

The behavior is a form of fraternization. It is punishable under the UCMJ.

The senior officer or NCO is “abandoning their rank” and at the moment of fraternizing, they showing favoritism and partiality at the expense of every other member of the military unit.

The senior officer should be removed from any leadership position and discharged from the military.

Their is no regulation yet is the respect to one another & traditionally in SFG. In conventional unit is different but allow with some Office & NCOIC who knows each other very good. This isn’t a big issue.

No known regulation. Military customs and traditions come first in public. What officers do in private that is between them, but would be set by the senior officer.