In this article, we report on crystal growth, density functional theory (DFT) calculations, and scintillation properties of TlCaX $_{3} (X =$ Cl, Br, I). Crystals were grown by the vertical Bridgman technique in silica ampoules. Crystals of TlCaCl 3 , TlCaBr 3 , and TlCaI 3 belong to the family of perovskites and have an orthorhombic crystal structure. All three compositions show bright emission under X-ray excitation peaking at 425, 470, and 545 nm, respectively. Light yield increases in the series Cl < Br < I [25 000–47 000 photons/MeV (ph/MeV)].