| Callsign: | WNJX-TV |
| Digital: | 31 (UHF) |
| Virtual: | 2, 4 |
| Location: | Mayagüez, Puerto Rico |
| Owner: | WAPA Media Group |
| Operator: | DT4: Telemundo Station Group via TBA |
| Licensee: | Televicentro of Puerto Rico, LLC |
| Sister Stations: | WAPA-TV, WTIN-TV, WKAQ, WKAQ-FM, WYEL |
| Facility Id: | 73336 |
| Coordinates: | 18.1477°N -66.9825°W |
| Licensing Authority: | FCC |
WNJX-TV (channel 4) is a Spanish-language independent television station in Mayagüez, Puerto Rico. It is a full-time satellite of San Juan–based WAPA-TV (channel 4), owned by WAPA Media Group. WNJX-TV's transmitter is located at Monte del Estado in Maricao, while its parent station maintains studios on Avenida Luis Vigoreaux in Guaynabo.
WNJX-TV's fourth digital subchannel operates as a full-time satellite of Telemundo owned-and-operated station WKAQ-TV (channel 2) under a time brokerage agreement with NBCUniversal's Telemundo Station Group. Branded on-air as Telemundo West, this subchannel is mapped to virtual channel 2.12 rather than 4.4. WNJX-DT4's parent station maintains studios on Roosevelt Avenue in San Juan.
The station's digital signal is multiplexed:
| Res. | Aspect | Short name | Programming | |
|---|---|---|---|---|
| 4.1 | WNJX-DT | WAPA-TV | ||
| 4.2 | WNJX-D2 | |||
| 4.3 | WNJX-D3 | WAPA 3 | ||
| 2.12 | WKAQ-DT | Telemundo | ||
| 2.22 | WKAQ .2 | Punto 2 |
WNJX-TV shut down its analog signal over UHF channel 22, on June 12, 2009, the official date on which full-power television stations in the United States transitioned from analog to digital broadcasts under federal mandate. The station's digital signal remained on its pre-transition UHF channel 23. Through the use of PSIP, digital television receivers display the station's virtual channel at VHF channel 4.