LGA 775 (land grid array 775), also known as Socket T, is an Intel desktop CPU socket. Unlike PGA CPU sockets, such as its predecessor Socket 478, LGA 775 has no socket holes; instead, it has 775 protruding pins which touch contact points on the underside of the processor (CPU).

Intel started selling LGA 775 (Socket T) CPUs with the 64-bit version of their 90 nm "Prescott"-based Pentium 4 HT.

The socket had an unusually long life span, lasting 7 years until the last processors supporting it ceased production in 2011. The socket was superseded by the LGA 1156 (Socket H) and LGA 1366 (Socket B) sockets.

(Note: Some of the processors listed here might not work on newer Intel based chipsets; see "LGA 775 compatibility" below.)

For LGA 775, the distance between the screw-holes for the heatsink is 72 mm. Such heat-sinks are not interchangeable with heatsinks for sockets that have a distance of 75 mm, such as LGA 1156, LGA 1155, LGA 1150, LGA 1151 and LGA 1200.

LGA 775 was the last Intel socket for desktops for which third-party companies manufactured chipsets. Nvidia was the last third-party manufacturer of LGA 775 chipsets (its final product was MCP7A family, marketed as GeForce 9300/9400, launched in October 2008), as other third-parties discontinued their products earlier. All chipsets for superseding sockets were exclusively designed and manufactured by Intel, a practice later also adopted by AMD when they first launched APUs in 2011 (Socket AM3+ processors, also launched in 2011, were usually paired with motherboard with AMD chipsets, but some motherboards using third-party chipsets were also manufactured, usually with Nvidia chipsets, as the Socket AM3+ design was directly extended from the earlier Socket AM3 design).

The force from the load plate ensures that the processor is completely level, giving the CPU's upper surface optimal contact with the heat sink or cold-water block fixed onto the top of the CPU to carry away the heat generated by the CPU. This socket also introduces a new method of connecting the heat dissipation interface to the chip surface and motherboard. With LGA 775, the heat dissipation interface is connected directly to the motherboard on four points, compared with the two connections of Socket 370 and the "clamshell" four-point connection of Socket 478. This was done to avoid the reputed danger of the heat sinks/fans of pre-built computers falling off in transit. LGA 775 was announced to have better heat dissipation properties than the Socket 478 it was designed to replace, but the Prescott core CPUs (in their early incarnations) ran much hotter than the previous Northwood-core Pentium 4 CPUs, and this initially neutralized the benefits of better heat transfer. However, the later Core 2 processors run at much lower temperatures than the Prescott CPUs they replaced.

Processors with lower TDP and clock speeds only used Thermal Interface Compound in between the die and the integrated heat spreader (IHS), while processors with higher TDP and clock speeds have the die soldered directly to the IHS, allowing for better heat transfer between the CPU and the integrated heat spreader.