Phosphor emission spectra are presented for MgSO4 doped with Dy, MgSO4 co-doped with Dy and Mn, MgSO4 co-doped with Dy and P, and MgSO4 co-doped with Dy, P and Cu. All spectral wavelengths are related to transitions in Dy3+ ions. In a broad wavelength band around ～660 nm, three dimensional glow curves at ～140 and ～190◦C in the MgSO4:Mn spectrum are due to emissions from Mn2+ ions. For MgSO4 co-doped with Dy and Mn the main glow peak occurs at ～380◦C, about 20◦C above the fourth glow peak obtained in MgSO4 doped with Dy. The emission spectra of the MgSO4: Dy, Mn phosphor show the competitive de-excitation processes between Dy3+ and Mn2+ ions. This indicates that rare earth and Mn ions in MgSO4: Dy, Mn form complex defects that dominate the traps and recombinations. The MgSO4: Dy glow peak at around 260◦C shifts in MgSO4: Dy, P to ～280◦C with enhanced intensity, while the ～360◦C glow peak remains in place with a slightly increased intensity. The enhanced transluminescence (TL) sensitivity obtained by co-doping with P is probably due to charge compensation. The relative intensities vary between the 480 and 580 nm band of the glow peaks while the temperature (～280◦C) is unchanged for MgSO4 co-doped with Dy, P and Cu. The Cu+2 or Cu+1 ions act as charge compensators to the Dy3+ ions and reduce the concentration of Mg2+ vacancies in MgSO4: Dy, P, Cu. This results in changes to the dose response characteristics.