The level at which listed firms in Nigeria disclose voluntary information is at an increasing rate yearly. This therefore, led to this research as to what factors influence this voluntary disclosure by insurance companies. This study primarily tries to determine the effects of firm size, profitability, and leverage on the content and degree of voluntary disclosure by insurance companies in Nigeria. All 15 insurance companies listed on the Nigerian Stock Exchange were used as the study's population, and a census sampling technique was applied to arrive at a sample size of ten (10) insurance companies. Data were collected from the insurance companies’ annual reports and accounts. Multiple regression analysis was used to investigate the effects of firm size, leverage, and profitability on voluntary disclosure. The results indicated that leverage and company size have a positive but insignificant effect on voluntary disclosure. Indeed, profitability has a negative but significant effect on voluntary disclosure. It is, therefore, recommended that insurance companies should embark on good corporate governance practices such as the voluntary disclosure of information in order to attract investors and improve their performance.