ABSTRACT Upconversion luminescence (UCL) materials based on the molecular lanthanide complexes have garnered increasing attention in diverse frontier fields in recent years. Compared with the intensively investigated lanthanide‐doped upconversion nanoparticles (UCNPs), the development of UCL lanthanide complexes needs strengthening, especially considering the controllable synthesis and flexible architecture characteristics of lanthanide complexes. In this review, we overview the recent advances in UCL lanthanide complex, varying from structural design to luminescent properties. The challenges remaining and future prospects for UCL lanthanide complex are also discussed. We hope that the review will bring more inspirations and possibilities for developing the field of molecular UCL.