This study investigates the relationship between firm complexity and stock price crash risk, distinguishing between business complexity and financial reporting complexity. While previous research primarily associates financial reporting complexity and increased crash risk, we propose that firm complexity can mitigate crash risk by incentivizing firms to engage in transparent disclosures. We employ firm complexity measures based on Loughran and McDonald's (2024) methodology. Our findings reveal that firm complexity is negatively associated with stock price crash risk, whereas financial reporting complexity exacerbates stock price crash risk by reducing information transparency. Further analyses show that external monitoring mechanisms, such as institutional ownership and analyst coverage, reinforce the mitigating effect of firm complexity on crash risk, whereas earnings management and adverse market conditions weaken this relationship.