The inland thornbill (Acanthiza apicalis) was originally described by English ornithologist John Gould in The Birds of Australia.

[3] The inland thornbill belongs to the genus Acanthiza, which now has three more species than the eleven outlined by Gould in The Birds of Australia.

The other species groups are one containing A. inornate, A. uropygialis, A, reguloides, and A. iredalei, one containing A. nana and A. lineata, one containing A. chrysorrhoa, and one for A.

[5] Inland thornbills have also been found to be proficient in mimicking the calls of other birds, such as the pied butcherbird (Cracticus nigrogularis), rufous whistler (Pachycephala rufiventris), bush stone-curlew (Burhinus grallarius), willie wagtail (Rhipidura leucophrys), grey fantail (Rhipidura albiscapa), and various cuckoos.

[18] Inland thornbills are long-lived, with one instance of the same bird being retrapped and banded over seven years after the first occasion.

Inland thornbills inhabit arid woodlands and scrubs throughout Australia, including the mulga (Acacia aneura) of the Mallee and the Gibson Desert.

[1] Typically, inland thornbills do not feed on the ground but instead in foliage as shrubs-canopy or generalised feeders.

[5] Inland thornbill breeding season is July to December with three white eggs with reddish freckles and blotches.

[5] Members of the genus Acanthiza and family Maluridae (Australasian wrens including the superb fairywren Malurus cyaneus) often foster the shining bronze-cuckoo (Chrysococcyx lucidus).

[1] The justification was that the inland thornbill is not limited to a niche habitat and has a distribution range above the Vulnerable listing threshold.

[25] In comparison, other studies have found that inland thornbills struggle to recover after a wildfire or drought.

[23] Poet John Kinsella wrote a poem for the British magazine the New Statesman, titled "Inland Thornbills".