Bror Jacob Adelborg was a Swedish naval officer, painter and draughtsman.

Brother Jacob was the son of Per Otto Adelborg and the father of Maria Adelborg, Gertrud Adelborg and Ottilia Adelborg.

Adelborg graduated from the Naval Academy in 1838 and was appointed second lieutenant in the navy the same year, after which he was promoted to first lieutenant in 1846, lieutenant commander in 1855, captain in 1858 and commander in 1864. From 1842 to 1846 he served in the British Navy.

Brother Jacob Adelborg joined the so-called Oxehufvud expedition to Latin America in 1840-41 as a midshipman and produced several marine paintings in watercolor and drawing.

He is represented in the National Museum with a watercolor pencil drawing and Uppsala University Library, and with fourteen works in the Maritime History Museum. Some of his drawings are reproduced in Axel Paulin's book Oxehufvud - en svensk viking (1947).

Adelborg was married to Hedvig af Uhr, daughter of the director Gustaf af Uhr.