[en] Highlights: • Energies and radiative transition data for the main states of the n$⩽$ 3 configurations in O-like Ions between Ar XI and Cr XVII are provided. • The multiconfiguration Dirac–Hartree–Fock and the relativistic configuration interaction methods are employed. • The most accurate and complete atomic data for O-like Ions between Ar XI and Cr XVII are provided. Using the multiconfiguration Dirac–Hartree–Fock and the relativistic configuration interaction methods, a consistent set of transition energies and radiative transition data for the main states of the $2s^{2}2p^4$, $2s2p^5$, $2p^6$, $2s^{2}2p^{3}3s$, $2s^{2}2p^{3}3p$, $2s^{2}2p^{3}3d$, $2s2p^{4}3s$, $2s2p^{4}3p$, and $2s2p^{4}3d$ configurations in O-like Ions between Ar XI ($Z=18$) and Cr XVII ($Z=24$) is provided. Our data set is compared with the NIST compiled values and previous calculations. The data are accurate enough for identification and deblending of new emission lines from hot astrophysical and laboratory plasmas. The amount of data of high accuracy is significantly increased for the $n=3$ states of several O-like ions, where experimental data are very scarce.