In Indonesia, the government invites business actors to jointly reduce greenhouse gas emissions through disclosure of carbon emissions. Disclosure of carbon emissions in Indonesia is still voluntary (voluntary disclosure), so not all companies disclose this information in their reports. The purpose of this article is to assess the impact of factors such as company size, profitability, company growth, environmental committees, and gender diversity on carbon emission disclosure by Indonesia’s manufacturing companies. For the study, the authors selected 16 manufacturing companies listed on the Indonesia Stock Exchange in 2014-2018. The activities of these companies are the subject of study. To measure the extent of the carbon emission disclosure, a checklist is developed based on the measurement sheet provided by the Carbon Disclosure Project (CDP). The CDP is an organisation based in the United Kingdom which supports companies and cities to disclose the environmental impact of major corporations. The main idea of the project is that environmental reporting and risk management should become a business norm in order to ensure sustainable development of the economy. The study results show that company size has an effect on the level of carbon emission disclosure. The bigger is the company – the greater is the pressure that results from its economic activities. Therefore, the government and the public pay more attention to such business entities. It prompts the company to disclose its carbon emissions. At the same time, such factors as profitability, company growth, environmental committee and gender diversity do not affect on carbon emission disclosure. It was found that the level of carbon emission disclosure among Indonesia’s manufacturing companies is very low, and therefore the government and society need to take measures to increase the responsibility of business entities for environmental pollution.