Monitoring and evaluation (M&E) of biodiversity has been heavily criticised. However, these criticisms have yet to be tested empirically across a range of geographical environments and institutions. We surveyed 243 protected area staff from 55 countries to describe how M&E is undertaken and to identify variables statistically associated with effective M&E. We found that M&E is routinely employed: 78% of respondents indicated that monitoring occurred and 64% responded that monitoring persisted for at least as long that a management action was implemented. However, our results suggested there is scope to improve the way that M&E is conducted: only 46% of respondents thought that M&E worked well, just 36% provided an example of monitoring informing management and 38% of respondents indicated that management is not undertaken in different ways to facilitate adaptive management. Monitoring and evaluation was generally perceived to be working better in non-government organisations (NGOs), where data are entered in existing databases, and where research and management staff work cooperatively. Monitoring had a greater probability of informing management where documented thresholds were in place that trigger management intervention and where monitoring data were stored in a publicly available database. Management was most likely to be implemented in different ways to facilitate adaptive management in NGOs, where management intervention options were documented, monitoring had persisted as long as the management action and where reporting is done regularly. The most common suggestions that respondents gave to improve M&E were increased funding, better science management integration, and improving organisational culture and commitment.