Photochromic organic compounds, which exhibit reversible color change upon light irradiation, are attractive functional materials for applications in memory devices, rewritable paper, sensors, and function inks. However, in the crystalline state, photochromic properties are related to the crystal structure and expected to be controlled by crystal structure modulation. Recently, crystal engineering studies targeting photochromic organic compounds have been conducted in the field of organic crystallography. Crystal engineering is an important concept in solid-state molecular research that enables designing of a crystal structure with desired properties and creation of new functional organic crystalline materials or precisely controlling the crystal properties. Herein, we introduce related studies for controlling photochromic properties by crystal engineering, classified by type: pre-crystallization crystal engineering (by co-crystallization and mixed crystal formation) and post-crystallization crystal engineering (by phase transition and solid-state reaction).