Border Security: Australia's Front Line (known as Nothing to Declare in the UK and Ireland) is an Australian factual television programme in the form of an observational documentary that airs on the Seven Network. The show follows the work of officers of the Department of Home Affairs, Australian Border Force, and biosecurity officers as they enforce Australian immigration, customs, quarantine and finance laws. All three of these government agencies cooperate with filming. Officers from the Australian Fisheries Management Authority and personnel from the Australian Defence Force have also appeared on the show.

Most of the programme is filmed at Sydney, Melbourne and Brisbane airports; scenes from the Sydney international mail arrival facility are also shown. Occasionally, the programme features other locations such as Perth Airport and Adelaide Airport, seaports, international mail centres, raids on workplaces suspected of employing persons contrary to the restrictions of their visa or immigrant status and the work of Australian Border Force vessels and aircraft in the waters of Northern Australia.

The series has so far produced 16 series as of 2022.

In July 2024, the Department of Agriculture, Fisheries and Forestry (Australia) announced filming of series 17 had been completed with episodes airing in the next 12 months.