Napier of Magdala Battery is a former coastal artillery battery on the south-western cliffs of the British Overseas Territory of Gibraltar, overlooking the Bay of Gibraltar. It also overlooks Rosia Bay from the north, as does Parson's Lodge Battery from the south. It contains one of two surviving Armstrong 100-ton guns.

An Armstrong gun was a uniquely designed type of rifled breech-loading field and heavy gun designed by Sir William Armstrong and manufactured in England beginning in 1855 by the Elswick Ordnance Company and the Royal Arsenal at Woolwich. Such guns involved a built-up gun construction system of a wrought-iron tube surrounded by a number of wrought-iron strengthening coils shrunk over the inner tube to keep it under compression.