The effect of strain rate, ε̇, and temperature, T, on the tension–compression asymmetry (TCA) in a dilute and wrought Mg alloy, AM30, over a temperature range that covers both twin accommodated deformation (below 250°C in compression) as well as dislocation-mediated plasticity (above 250°C) has been investigated. For this purpose, uniaxial tension and compression tests were conducted at T ranging from 25 to 400°C with ε̇ varying between 10−2 and 10s−1. In most of the cases, the stress–strain responses in tension and compression are distinctly different; with compression responses ‘concaving upward,’ due to {101̄2} tensile twinning at lower plastic strains followed by slip and strain hardening at higher levels of deformation, for T below 250°C. This results in significant levels of TCA at T<250°C, reducing substantially at high temperatures. At T=150 and 250°C, high ε̇ leads to high TCA, in particular at T=250°C and ε̇=10s−1, suggesting that twin-mediated plastic deformation takes precedence at high rates of loading even at sufficiently high T. TCA becomes negligible at T=350°C; however at T=400°C, as ε̇ increases TCA gets higher. Microscopy of the deformed samples, carried out by using electron back-scattered diffraction (EBSD), suggests that at T>250°C dynamic recrystallization begins between accompanied by reduction in the twinned fraction that contributes to the decrease of the TCA.