| Attribute | Value |
| General |
| Production from | 2019 year |
| Make | KTM |
| Model | KTM 125 SX |
| Category | Cross / motocross |
| Engine and transmission |
| Engine type | Single cylinder, two-stroke |
| Valves per cylinder | Add |
| Fuel system | Carburettor. Mikuni TMX |
| Engine details | Reed intake. |
| Displacement | 124.8 cm³ |
| Power | Add |
| Max RPM | Add |
| Fuel consumption | Add |
| Cooling system | Liquid |
| Transmission type,final drive | Chain |
| Torque | Add |
| Bore | 54 mm |
| Stroke | 54.5 mm |
| Gearbox | 6-speed |
| Greenhouse gases | Add |
| Fuel control | Add |
| Emission details | Add |
| Driveline | 13:50. Primary drive: 23:73. |
| Ignition | Kokusan EMS |
| Clutch | Wet multi-disc clutch, hydraulically actuated |
| Lubrication system | Add |
| Compression | Add |
| Exhaust system | Add |
| Chassis |
| Front suspension | WP-USD, AER 48, Ø 48 mm |
| Rear suspension | WP shock absorber with linkage |
| Front brakes | Single disc. Brake calipers on floating bearings |
| Rear brakes | Single disc. Brake calipers on floating bearings |
| Diameter | 220 mm |
| Frame type | Chrome-molybdenum steel central-tube frame |
| Front tyre | Add |
| Rear tyre | Add |
| Seat | Add |
| Wheels | CNC machined hubs. Excel rims. Wire spoked. |
| Front wheel travel | 310 mm |
| Rear wheel travel | 300 mm |
| Trail | Add |
| Rake (fork angle) | 26.1 degree |
| Other |
| Battery capacity | Add |
| Starter | Kick |
| Color options | |
| Carrying capacity | Add |
| Light | Add |
| Instruments | Add |
| Electrical Voltage | Add |
| Dimensions |
| Wheelbase | 1,485 mm |
| Kerb weight | Add |
| Dry weight | 87 kg |
| Power/weight ratio | Add |
| Overall height | Add |
| Overall length | Add |
| Overall width | Add |
| Seat height | 950 mm |
| Alternate seat height | Add |
| Ground clearance | 375 mm |
| Front percentage of weight | Add |
| Rear percentage of weight | Add |
| Performance |
| Top speed | Add |
| Acceleration 0-100 km/h | Add |
| Length | Add |
| Reserve fuel capacity | Add |
| Fuel capacity | 7.5 l |
| Oil capacity | Add |
| Width | Add |
| Height | Add |