| Type: | town |
| Middle Arm | |
| State: | nsw |
| Coordinates: | -34.5975°N 149.7278°W |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location in New South Wales |
| Lga: | Upper Lachlan Shire |
| County: | Argyle |
| Parish: | Wayo |
| Region: | Southern Tablelands |
| Postcode: | 2580[1] |
| Pop: | 377 |
| Elevation: | 755 |
| Stategov: | Goulburn |
| Fedgov: | Hume |
| Dist1: | 16 |
| Dir1: | N |
| Location1: | Goulburn |
| Dist2: | 81 |
| Dir2: | WSW |
| Location2: | Moss Vale |
| Dist3: | 42 |
| Dir3: | ESE |
| Location3: | Crookwell |
| Dist4: | 209 |
| Dir4: | SW |
| Location4: | Sydney |
| Near-N: | Myrtleville |
| Near-Ne: | Chatsbury |
| Near-E: | Tarlo |
| Near-Se: | Goulburn |
| Near-S: | Kingsdale |
| Near-Sw: | Wayo |
| Near-W: | Woodhouselee |
| Near-Nw: | Roslyn |
Middle Arm is a locality in the Upper Lachlan Shire, in the Southern Tablelands region of New South Wales, Australia. At the, it had a population of 377.
As of the 2021 Australian census, 377 people resided in Middle Arm, up from 362 in the . The median age of persons in Middle Arm was 46 years. There were more males than females, with 53.5% of the population male and 46.5% female. The average household size was 2.7 people per household.