Alfred Peter Friedrich von Tirpitz (; born Alfred Peter Friedrich Tirpitz; 19 March 1849 – 6 March 1930) was a German grand admiral and State Secretary of the German Imperial Naval Office, the administrative branch of the German Imperial Navy from 1897 until 1916.

Prussia never had a major navy, nor did any of the other German states before the German Empire was formed in 1871. Tirpitz took the modest Imperial Navy and, beginning in the 1890s, turned it into a world-class force that could threaten Britain's Royal Navy. However, during World War I, his High Seas Fleet proved unable to end Britain's command of the sea and its chokehold on Germany's economy. The one great engagement at sea, the Battle of Jutland, ended in a narrow German tactical victory but a strategic failure.

As the High Seas Fleet's limitations became increasingly apparent during the war, Tirpitz became an outspoken advocate for unrestricted submarine warfare, a policy which would ultimately bring Germany into conflict with the United States. By the beginning of 1916, he was dismissed from office and never regained power. Following his dismissal, he became Chairman of the far-right German Fatherland Party, an ideological precursor to the German National People's Party.

Family and early life Tirpitz was born in Küstrin (today Kostrzyn in Poland) in the Prussian province of Brandenburg, the son of lawyer and later judge Rudolf Tirpitz (1811–1905). His mother was the daughter of a doctor. Tirpitz grew up in Frankfurt (Oder). He recorded in his memoirs that as a child he was a mediocre pupil.

Tirpitz spoke English fluently and was sufficiently at home in Britain that he sent his two daughters Ilse and Margot to Cheltenham Ladies' College.

On 18 November 1884 he married Maria Augusta Lipke (born 11 October 1860 in Schwetz, West Prussia, died after 1941). On 12 June 1900 he was elevated to the Prussian nobility, becoming von Tirpitz. He had four children: Max, Wolfgang, Ilse (born 1885) and Margot (born 1888). His son, Oberleutnant zur See Wolfgang von Tirpitz, was taken prisoner of war after the sinking of in the Battle of Heligoland Bight on 28 August 1914. Ilse married diplomat Ulrich von Hassell who was executed in 1944 as an anti-Hitler activist. Their daughter and her young sons were then taken as hostages. She wrote of the experience in A Mother's War.

Naval career Tirpitz joined the Prussian Navy more by accident than design when a friend announced that he was doing so. Tirpitz decided he liked the idea and with the consent of his parents became a naval cadet at the age of 16, on 24 April 1865. He attended Kiel Naval School. Within a year Prussia was at war with Austria. Tirpitz became a midshipman (Seekadett) on 24 June 1866 and was posted to a sailing ship patrolling the English Channel. In 1866 Prussia became part of the North German Confederation, the navy officially became that of the confederation and Tirpitz joined the new institution on 24 June 1869.

On 22 September 1869 he had obtained the rank of Unterleutnant zur See (sub-lieutenant) and served on board the ironclad . During the Franco-Prussian War the Prussian Navy was greatly outnumbered and so the ship spent the duration of the war at anchor, much to the embarrassment of the navy. During the early years of Tirpitz's career, Prussia and Great Britain were on good terms and the Prussian Navy spent much time in British ports. Tirpitz reported that Plymouth was more hospitable to German sailors than was Kiel, while it was also easier to obtain equipment and supplies there, which were of better quality than available at home. At this time the British Royal Navy was pleased to assist that of Prussia in its development and Prussian officers had considerable respect for their British counterparts.Massie p. 166

Development of torpedoes Unification of Germany in 1871 again meant a change of name, to the German Imperial Navy. On 25 May 1872 Tirpitz was promoted to Leutnant zur See (lieutenant at sea) and on 18 November 1875 to Kapitänleutnant (captain-lieutenant). In 1877 he was chosen to visit the Whitehead Torpedo Works at Fiume and afterwards was placed in charge of the German torpedo section, later renamed the Torpedo Inspectorate. By 1879 a working device had been produced, but even under demonstration conditions Tirpitz reckoned it was as likely to miss a target as to hit it. On 17 September 1881 he became Korvettenkapitän (corvette captain). From developing torpedoes, Tirpitz moved on to developing torpedo boats to deliver them. The State Secretary for the Navy, Leo von Caprivi, was a distant relation, and Tirpitz now worked with him on the development of tactics. Caprivi envisioned that the boats would be used defensively against their most likely enemy, France, but Tirpitz set about developing plans to attack the French home port of Cherbourg-en-Cotentin. Tirpitz later described his time with torpedo boats as "the eleven best years of my life".Massie p. 167

Strategic development of the navy In 1887 the torpedo boats escorted Prince Wilhelm to attend the Golden Jubilee celebrations of his grandmother, Queen Victoria. This was the first time Tirpitz met Wilhelm. In July 1888 Caprivi was succeeded by Alexander von Monts. Torpedo boats were no longer considered important, and Tirpitz requested transfer, commanding the ironclads and then . He was promoted to captain (Kapitän zur See) 24 November 1888 and in 1890 became chief of staff of the Baltic Squadron. On one occasion the Kaiser was attending dinner with the senior naval officers at Kiel and asked their opinion on how the navy should develop. Finally the question came to Tirpitz and he advised building battleships. This was an answer which appealed to the Kaiser, and nine months later he was transferred to Berlin to work on a new strategy for creating a high seas fleet. Tirpitz appointed a staff of officers he had known from his time with the torpedo boats and collected together all sorts of vessels as stand-in battleships to conduct exercises to test out tactics. On 1 December 1892 he made a presentation of his findings to the Kaiser. This brought him into conflict with the Navy State Secretary, Admiral Friedrich von Hollmann. Hollmann was responsible for procurement of ships, and had a policy of collecting ships as funding permitted. Tirpitz had concluded that the best fighting arrangement was a squadron of eight identical battleships, rather than any other combination of ships with mixed abilities. Further ships should then be added in groups of eight. Hollmann favoured a mixed fleet including cruisers for long-distance operations overseas. Tirpitz believed that in a war no number of cruisers would be safe unless backed up by sufficient battleships.

Kapitän zur See (captain at sea) Tirpitz became chief of the naval staff in 1892 and was made a Konteradmiral (rear admiral) in 1895.

In autumn 1895, frustrated by the non-adoption of his recommendations, Tirpitz asked to be replaced. The Kaiser, not wishing to lose him, asked instead that he prepare a set of recommendations for ship construction. This was delivered on 3 January 1896, but the timing was bad as it coincided with raids into the Transvaal in Southern Africa by pro-British forces against the pro-German Boers. The Kaiser immediately set his mind to demanding cruisers which could operate at a distance and influence the war. Hollman was tasked with obtaining money from the Reichstag for a building programme, but failed to gain funding for enough ships to satisfy anyone. Imperial Chancellor Hohenlohe saw no sense in naval enlargement and reported back that the Reichstag opposed it. Admiral Gustav von Senden-Bibran, Chief of the Naval Cabinet, advised that the only possibility lay in replacing Hollmann: Wilhelm impulsively decided to appoint Tirpitz.Massie, pp. 169–170

Meanwhile, however, Hollmann had obtained funding for one battleship and three large cruisers. It was felt that replacing him before the bill had completed approval through the Reichstag would be a mistake. Instead, Tirpitz was placed in charge of the German East Asia Squadron in the Far East but with a promise of appointment as secretary at a suitable moment. The cruiser squadron operated from British facilities in Hong Kong which were far from satisfactory as the German ships always took second place for available docks. Tirpitz was instructed to find a suitable site for a new port, selecting four possible sites. Although he initially favoured the bay at Kiautschou/Tsingtao, others in the naval establishment advocated a different location and even Tirpitz wavered on his commitment in his final report. A "lease" on the land was acquired in 1898 after it was fortuitously occupied by German forces. On 12 March 1896 the Reichstag cut back Hollmann's appropriation of 70 million marks to 58 million, and Hollman offered his resignation. Tirpitz was summoned home and offered the post of secretary of the Imperial Navy office (Reichsmarineamt). He went home the long way, touring the United States on the way and arriving in Berlin 6 June 1897. He was pessimistic of his chances of succeeding with the Reichstag.Massie p. 171

State Secretary of the Imperial Navy Office On 15 June Tirpitz presented a memorandum on the makeup and purpose of the German fleet to the Kaiser. This defined the principal enemy as Great Britain, and the principal area of conflict to be that between Heligoland and the Thames. Cruiser warfare around the globe was deemed impractical because Germany had few bases to resupply ships, while the chief need was for as many battleships as possible to take on the British fleet. A target was outlined for two squadrons of eight battleships, plus a fleet flagship and two reserves. This was to be completed by 1905 and cost 408 million marks, or 58 million per year, the same as the existing budget. The proposal was innovative in several ways. It made a clear statement of naval needs, whereas before the navy had grown piecemeal. It set out the programme for seven years ahead, which neither the Reichstag nor the navy should change. It defined a change in German foreign policy so as to justify the existence of the fleet: Great Britain up to this point had been friendly, now it was officially an enemy. The Kaiser agreed to the plan and Tirpitz retired to St Blasien in the Black Forest with a team of naval specialists to draft a naval bill for presentation to the Reichstag. Information about the plan leaked out to Admiral Knorr, head of the Naval High Command. Tirpitz agreed to a joint committee to discuss changes in the navy, but then arranged that it never receive any information. Similarly, he arranged a joint committee with the Treasury State Secretary to discuss finance, which never discussed anything. Meanwhile, he continued his best efforts to convince the Kaiser and Chancellor, so that in due course he could announce the issues had already been decided at a higher level and thereby avoid debate.Massie pp. 172–174