"Band of brothers" was a phrase used by Rear-Admiral Horatio Nelson to refer to the captains under his command just before and at the Battle of the Nile in 1798. The phrase, taken from Shakespeare's St Crispin's Day Speech of Henry V, later came to be more generally applied to his relationship with the captains and men under his command, such as at the Battle of Trafalgar.

One of Nelson's earliest uses of the phrase is in a letter written shortly after the Spanish entry into the war. Nelson, eager for action, had hoped to be given command of a squadron cruising off the Spanish coast, but was passed over. Dismayed, he wrote of his indignation and disappointment, but added:

Yet, if I know my own thoughts, it is not for myself, or on my own account chiefly, that I feel the sting and the disappointment! No! it is for my brave officers; for my noble-minded friends and comrades. Such a gallant set of fellows! Such a band of brothers! My heart swells at the thought of them!

Shortly afterwards, the French fleet sailed from Toulon under the command of Vice-Admiral Brueys, carrying Napoleon and a French invasion force bound for Malta and Egypt. The British commander-in-chief of the Mediterranean Fleet, Admiral Sir John Jervis reinforced Nelson with several ships of the line and sent him in search of the French. Nelson was initially unsuccessful, missing the French when they passed by, and invaded, Malta in June. They then sailed on to Egypt, and carried out a successful landing at Alexandria in early July. Nelson finally caught up with the French fleet on 1 August, anchored in Aboukir Bay. Nelson immediately prepared an attack, taking the French by surprise, and won a decisive victory, capturing or burning most of the fleet.

Under Nelson's command at this time were:

Of the brothers, Nelson had already served alongside several. Miller had commanded HMS Captain as Nelson's flag captain at the Battle of Cape St Vincent in 1797, where Troubridge had commanded HMS Culloden. The Battle of Santa Cruz de Tenerife some months later reunited Miller and Troubridge, whilst Captains Hood and Thompson were also present. Andrew Lambert has written that the captains at the Nile were "outstanding officers", though he excepted Edward Berry, due to being "prone to serious errors of judgement at sea and in combat". In the immediate aftermath of the battle the surviving captains agreed to commission a sword and a portrait of Nelson as a "proof of their esteem" for his "prompt decision and intrepid conduct", prompting Nelson to stress that "the conduct of every officer was equal". Nelson wished to avoid the bitter controversy that had erupted after the Glorious First of June, when Lord Howe's dispatch had omitted mention of many of the captains who had fought under him. A similar situation had followed the Battle of Cape St Vincent, at which Nelson himself had fought. Several captains were passed over in Jervis's account, and became jealous of those who had had their exploits reported.

Nelson therefore acted to forestall any criticism, and also to ensure that all his captains were rewarded with Naval Gold Medals. This was particularly important as one of Nelson's closest confidants, Thomas Troubridge, had played virtually no part in the battle, after his ship had run aground before reaching the French. Nelson had an uncomfortable relationship with Saumarez, the senior captain in the squadron, and thus ex officio his second in command. A. T. Mahan thought that Troubridge was likely Nelson's preferred choice, but he found himself unable to replace Saumarez. When writing his dispatch Nelson made no mention of either Saumarez or Troubridge being senior to one another, either to avoid naming Saumarez as his second in command, or to spare Troubridge embarrassment after the grounding of his ship". After Lord Howe's dispatch, a number of captains at the Glorious First of June had not been awarded medals, and by employing the term "band of brothers", Nelson declared that all of the captains were worthy of recognition. His tactic was successful, even Howe had commented that the battle was particularly significant as "every captain distinguished himself".

After the battle Nelson wrote a number of letters and dispatches, often using the term "band of brothers" to refer to those who had fought alongside him. To his commanding officer, Lord St Vincent, he wrote, referring to Alexander Ball,