Buenos Aires Province Senate

{{Infobox legislature

| background_color = #0061B6

| name = Senate of Buenos Aires Province

| native_name = Senado de la Provincia de Buenos Aires

| logo_pic = Coat of arms of the Buenos Aires Province.svg

| logo_res = 70px

| house_type = Upper house of the Legislature of Buenos Aires Province

| leader1_type = President

| leader1 = Verónica Magario

| party1 = UP

| election1 = 10 December 2019

| leader2_type = 1st Vice President

| leader2 = Luis Vivona

| party2 = UP

| election2 = 10 December 2021

| leader3_type = 2nd Vice President

| leader3 = Alejandro Cellillo

| party3 = UCR

| election3 = 10 December 2021

| leader4_type = 3rd Vice President

| leader4 = Ayelen Durán

| party4 = UP

| election4 = 10 December 2021

| members = 92

| structure1 = Senado de la Provincia de Buenos Aires (2023-2025).svg

| structure1_res = 250px

| political_groups1 =

• {{Color box|#00A0E4|border=darkgray}} Union for the Homeland (21)
• {{Color box|#FFD800|border=darkgray}} PRO (11)
• {{Color box|{{party color|Radical Civic Union}}|border=darkgray}} UCR–CF (8)
• {{Color box|{{party color|La Libertad Avanza}}|border=darkgray}} La Libertad Avanza (4)
• {{Color box|#4e66ad|border=darkgray}} Free Buenos Aires (1)
• {{Color box|#003179|border=darkgray}} People's Right (1)

| last_election1 = 22 October 2023

| previous_election1 =

| voting_system1 = Party-list proportional representation
Hare quota

| meeting_place = Legislative Palace of the Province of Buenos Aires
La Plata, Argentina

| session_room = Senado Provincia de Buenos Aires.jpg

| website = http://www.senado-ba.gov.ar/

}}

The Senate of Buenos Aires Province ({{langx|es|Senado de la provincia de Buenos Aires}}) is the upper house of the Legislature of Buenos Aires Province, the largest and most populous of Argentina's provinces. It comprises 43 members elected in eight multi-member constituencies known as Electoral Sections. The number of senators that correspond to each of the electoral sections is proportional to their population, as observed in the results of every nationwide census conducted in Argentina every 10 years. Seats may only be added to adjust the proportionality of each section, but never reduced.{{cite web|url=https://normas.gba.gob.ar/documentos/VGW7pIWV.html|work=Normas {{!}} Gobierno de la Provincia de Buenos Aires|title=Ley N° 5.109|access-date=27 December 2021|language=es}}

As in the National Chamber of Deputies and most other provincial legislatures, elections to the Senate are held every two years, so that half of its members are up in each election. The same system is employed in the provincial Chamber of Deputies.{{Cite web |url=http://www.hcdiputados-ba.gov.ar/ |title=Buenos Aires Province Chamber of Deputies Official Site |access-date=2011-10-04 |archive-url=https://web.archive.org/web/20090221040912/http://www.hcdiputados-ba.gov.ar/ |archive-date=2009-02-21 |url-status=dead }}

The Senate was established with the promulgation of the Constitution of the State of Buenos Aires, a short-lived secessionist state, in 1854. Originally located in the City of Buenos Aires, the provincial legislature was moved to La Plata following that city's establishment in 1882. The body meets in the Legislative Palace, designed by Hannover architects Gustav Heine and Georg Hagemann in 1883 and completed in 1888.{{cite web|url=http://www.hcdiputados-ba.gov.ar/index.php?id=historias|title=Historias|publisher=Cámara de Diputados de la Provincia de Buenos Aires|access-date=2012-09-22|archive-url=https://web.archive.org/web/20121001205557/http://www.hcdiputados-ba.gov.ar/index.php?id=historias|archive-date=2012-10-01|url-status=dead}}