| Official Name: | Post Proper Northside |
| Other Name: | Barangay 30 |
| Settlement Type: | Barangay |
| Seal Size: | 100x100px |
| Pushpin Map: | Metro Manila |
| Subdivision Type: | Country |
| Subdivision Name: | Philippines |
| Subdivision Type1: | Region |
| Subdivision Name1: | National Capital Region |
| Subdivision Type2: | City |
| Subdivision Name2: | Taguig |
| Subdivision Type3: | District |
| Subdivision Name3: | 2nd district of Makati |
| Government Type: | Barangay |
| Leader Title: | Barangay Captain |
| Leader Name: | Richard Pasadilla |
| Leader Title1: | Barangay Councilors |
| Leader Name1: | --> |
| Leader Title2: | SK Chairperson |
| Leader Name2: | Joshua Daniel Espejo |
| Leader Title3: | SK Councilors |
| Leader Name3: | --> |
| Established Title: | Established |
| Established Date: | December 11, 1972 |
| Established Title2: | Transfer of control to Taguig |
| Established Date2: | 2023 |
| Area Total Km2: | 2.376 |
| Population As Of: | 2020 |
| Population Total: | 57,940 |
| Population Density Km2: | auto |
| Timezone: | PST |
| Utc Offset: | +8 |
| Coordinates: | 14.5627°N 121.0544°W |
| Postal Code Type: | Postal Code |
| Postal Code: | 1647 |
| Area Code Type: | Area Code |
| Area Code: | 02 |
Post Proper Northside, also known as Post Proper North, Barangay 30, or simply Northside, is one of the 38 barangays of Taguig, Philippines. It is the fourth most populous barangay in the city, with a population of 57,940 according to the 2020 census. It is one of the ten Embo barangays.
Post Proper Northside was established in 1972 and has overlapping territorial claims with Barangay Fort Bonifacio, which controls the Bonifacio Global City (BGC) after it was held by Barangay Ususan. Following the resolution of the Makati–Taguig territorial dispute, which resulted in Taguig victory, the territorial jurisdiction of Post Proper Northside was transferred from Makati to Taguig in 2023.
The administrative division claims an area of 2.376sqkm.[1] The entire area is currently under the jurisdiction of Taguig, mostly overlapping its barangay Fort Bonifacio. Most of Bonifacio Global City is covered by the barangay. The non-overlapping portion, meanwhile, is a small area located between barangays Cembo and West Rembo which consists of Makati City Jail, Teachers' Compound, and Villa Kalayaan, all situated to the north of Kalayaan Avenue. Its barangay hall was once located in front of Makati City Jail until it was transferred to Macda Compound in Barangay Cembo upon the construction of the Santa Monica–Lawton Bridge.
As per the 2020 census by the Philippine Statistics Authority, the barangay has a population of 57,940, making it the second most populous barangay of Makati at that time. Since it was transferred to Taguig, it is currently the fourth most populous barangay of the city.
Like all other barangays of the Philippines, the barangay government of Post Proper Northside consists of the barangay captain, its chief executive and presiding officer of the seven-member Sangguniang Barangay. It also has a Sangguniang Kabataan (SK) chairman and a seven-member SK council. The aforementioned officials are all elected. Its seat of government, the barangay hall, is located along J. P. Rizal Avenue in Cembo. The previous location was along Lawton Avenue.
Its incumbent barangay captain is Richard Pasadilla, while its incumbent SK Chairman is Joshua Daniel Espejo.