Labor Zionism or Socialist Zionism (Hebrew: צִיּוֹנוּת סוֹצְיָאלִיסְטִית, translit. tziyonut sotzyalistit) is the left wing of the Zionist movement. It was, for many years, the most significant tendency among Zionists and Zionist organizations. It saw itself as the Zionist sector of the historic Jewish labor movements of Eastern and Central Europe, eventually developing local units in most countries with sizable Jewish populations. Unlike the "political Zionist" tendency founded by Theodor Herzl and advocated by Chaim Weizmann, Labor Zionists did not believe that a Jewish state would be created simply by appealing to the international community or to a powerful nation such as Britain, Germany or the Ottoman Empire. Rather, Labor Zionists believed that a Jewish state could only be created through the efforts of the Jewish working class settling in Palestine and constructing a state through the creation of a progressive Jewish society with rural kibbutzim and moshavim and an urban Jewish proletariat.
Labor Zionism grew in size and influence and eclipsed "political Zionism" by the 1930s both internationally and within the British Mandate of Palestine where Labor Zionists predominated among many of the institutions of the pre-independence Jewish community Yishuv, particularly the trade union federation known as the Histadrut. The Haganah – the largest Zionist paramilitary defense force – was a Labor Zionist institution and was used on occasion (such as during the Hunting Season) against right-wing political opponents or to assist the British Administration in capturing rival Jewish militants.