Context. Young stars and multi-planet systems are two types of primary objects that allow us to study, understand, and constrain planetary formation and evolution theories. Aims. We validate the physical nature of two Neptune-sized planets transiting TOI-942 (TYC 5909-319-1), a previously unacknowledged young star (50₋₂₀⁺³⁰ Myr) observed by the TESS space mission in Sector 5. Methods. Thanks to a comprehensive stellar characterization, TESS light curve modeling and precise radial-velocity measurements, we validated the planetary nature of the TESS candidate and detected an additional transiting planet in the system on a larger orbit. Results. From photometric and spectroscopic observations we performed an exhaustive stellar characterization and derived the main stellar parameters. TOI-942 is a relatively active K2.5V star (log R′_HK = −4.17 ± 0.01) with rotation period P_rot = 3.39 ± 0.01 days, a projected rotation velocity v sin i_⋆ = 13.8 ± 0.5 km s⁻¹, and a radius of ~0.9 R_⊙. We found that the inner planet, TOI-942 b, has an orbital period P_b = 4.3263 ± 0.0011 days, a radius R_b = 4.242_−0.313^+0.376 R_⊕, and a mass upper limit of 16 M_⊕ at 1σ confidence level. The outer planet, TOI-942 c, has an orbital period P_c = 10.1605_−0.0053^+0.0056 days, a radius R_c = 4.793_−0.351^+0.410 R_⊕, and a mass upper limit of 37 M_⊕ at 1σ confidence level.