Pinhas Rutenberg (Russian: Пётр Моисеевич Рутенберг, Pyotr Moiseyevich Rutenberg; Hebrew: פנחס רוטנברג; 5 February 1879 – 3 January 1942) was a Russian businessman, hydraulic engineer and political activist. In Russia, he was a member of the Socialist Revolutionary Party and fled due to the Bolshevik revolution. During World War I, he was among the founders of the Jewish Legion and of the American Jewish Congress. Later, he immigrated to Mandatory Palestine and used his education and diplomacy to obtain a concession for production and distribution of electric power and founded the Palestine Electric Corporation in 1923, currently the Israel Electric Corporation. A vocal and committed Zionist, Rutenberg also participated in establishing the Haganah, and founded Palestine Airways. He subsequently served as a president of the Jewish National Council.

Pinhas Rutenberg was born in the town of Romny, north of Poltava, Russian Empire, now in Ukraine (also the hometown of Haim Arlosoroff and three of the founders of the first kibbutz, Degania). After graduating from a practical high school, he enrolled to the Technology Institute in Saint Petersburg and joined the Socialist-Revolutionary Party (also known as the S.R. or Eser party). He worked as a workshop manager at the Putilov plant, the largest Petersburg factory. The plant was a center of the Assembly of Russian Factory and Plant Workers [ru], founded in 1903 by a popular working-class leader, Father George Gapon. Gapon collaborated in secret with the Police Department (the Okhrana), which believed this to be the way to control the workers' movement. Rutenberg became Gapon's friend, which made him a noticeable figure in the S.R. party.

For Sunday, 22 January [O.S. 9 January] 1905, Gapon organised a "peaceful workers' procession" to the Winter Palace in order to present a petition to the Emperor. Rutenberg participated, with his party's approval. In a tragic turn of events, army pickets fired directly into the crowd, and hundreds were killed. Amid the panic, Rutenberg retained self-control and actually saved Gapon's life, taking him away from gunfire. This incident, known as Bloody Sunday, sparked the Russian Revolution of 1905.

Gapon and Rutenberg fled abroad, being welcomed in Europe both by prominent Russian emigrants (such as Georgy Plekhanov and Vladimir Lenin), and by French socialist leaders (such as Jean Jaurès and Georges Clemenceau). Before the end of 1905, Rutenberg returned to Russia, and Gapon followed him.

Gapon soon revealed to Rutenberg his contacts with the police and tried to recruit him, too, reasoning that double loyalty was helpful to the workers' cause. However, Rutenberg betrayed his trust and reported this provocation to his party leaders, Yevno Azef and Boris Savinkov. Azef demanded that the traitor be put to death. Ironically, he was in fact an agent provocateur himself, exposed by Vladimir Burtsev in 1908.

On 26 March 1906, Gapon arrived to meet Rutenberg in a rented cottage outside Saint Petersburg, and after a month Gapon was found there hanged. Rutenberg asserted later that Gapon was condemned by a comrades' court and that three S.R. party combatants overheard their conversation from the next room. After Gapon had repeated his collaboration proposal, Rutenberg called the comrades into the room and he left. When he returned, Gapon was dead.

However, the S.R. party leadership refused to assume responsibility, announcing that the execution was undertaken by Rutenberg individually and that the cause was a personal one, denying ever having sent their comrades to the meeting on 26 March. Rutenberg was then condemned and expelled from the party.

Forced to emigrate, Rutenberg settled in Italy. Away from politics, he concentrated on hydraulic engineering. Pondering on specific Jewish problems, he became convinced that the solution was to establish a national home for the Jewish people.