The Office of National Assessments is an Australian government body responsible for the analysis of intelligence data related to foreign affairs, roughly equivalent to the analysis departments of other intelligence agencies.

Though not secret, the organisation usually attracts little attention - a striking exception occurring in 2001 when the Prime Minister, John Howard used an ONA assessment to publicly bolster his claims about the asylum seekers on MV Tampa in the Tampa affair. The ONA assessment was later leaked in its entirety and showed its assessment was based on press quotes from various government ministers.