Lead halide perovskite nanocrystals (LHP NCs) have rapidly emerged as one of the most promising materials for optical sources, photovoltaics, and sensor fields. The controlled synthesis of LHP NCs with high monodispersity and precise size tunability has been a subject of intensive research in recent years. However, due to their ionic nature, LHP NCs are usually formed instantaneously, and the corresponding nucleation and growth are difficult to monitor and regulated. In this Perspective, we summarize the representative attempts to achieve controlled synthesis of LHP NCs. We first highlight the burst nucleation and rapid growth characteristics of conventional synthesis methods. Afterward, we introduce the scheme of changing the LHP NCs into kinetically dominant, continuously size-tunable synthesis via nucleation-growth decoupling. We also summarize methods to eliminate undesired ripening effects and achieve homogeneous size distribution through rational ligand selection and solvent engineering. We hope this Perspective will facilitate the development of controlled LHP NCs synthesis protocols and advance the understanding of crystal growth fundamentals of perovskite materials.