Giovanni Battista Pacichelli FRS (1641 – 1695) was an Italian abbot, scholar and traveller.
In 1668 he published his first work, Il Giosia del Vaticano, dedicated to Pope Clement IX.
He spent some time in Amsterdam, where he visited the collections of Witsen, Grill, Occo and van der Hem.
After a brief stay in Cologne, in 1676 he undertook a long journey through Sweden, Denmark, Austria, Poland and Hungary.
His masterpiece, Il Regno di Napoli in Prospettiva (The Kingdom of Naples in Perspective), was published posthumously in 1703.
Pacichelli was a friend and correspondent of many of the foremost scholars of the day, including Angelico Aprosio, Nicolas Steno, René-François de Sluse and Nicolaas Heinsius.