Penryn is the code name of a mobile processor from Intel that is sold in varying configurations such as Core 2 Solo, Core 2 Duo, Core 2 Quad, Pentium and Celeron.

During development, Penryn was the Intel code name for the 2007/2008 "Tick" of Intel's Tick-Tock cycle which shrunk Merom to 45 nanometers as CPUID model 23. The term "Penryn" is sometimes used to refer to all 45 nm chips with the Core architecture.

Chips with Penryn architecture come in two sizes, with 6 MB and 3 MB L2 cache.

Low power versions of Penryn are known as the Penryn-L; these are single-core processors. The Penryn-QC quad-cores are made from two chips with two cores and 6 MB of cache per chip.

The desktop version of Penryn is Wolfdale and the dual-socket server version is Wolfdale-DP. Penryn-QC is related to Yorkfield on the desktop and Harpertown in servers. The MP server Dunnington chip is a more distant relative based on a different chip but using the same 45 nm Core microarchitecture.

Penryn was replaced by the Nehalem-based Arrandale (dual core) and Clarksfield (quad core).

The successor to the Merom core for the Core 2 Duo T5000/T7000 series mobile processors, code-named Penryn, debuted on the 45 nanometer process. Many details about Penryn appeared at the April 2007 Intel Developer Forum. Intel's new 45 nm Penryn-based Core 2 Duo and Core 2 Extreme processors were released on January 6, 2008. The new processors launched exclusively with a TDP of 35 W; later releases were more energy efficient. HP began to offer the first model, the T9500, from late January 2008. The T9500 offered a 2.6 GHz clock rate, higher than all but the Extreme Edition of the Merom range, and 6 MB (rather than 4 MB) of Level 2 Cache.

Important advances included the addition of new instructions including SSE4 (also known as Penryn New Instructions) and new fabrication materials; most significantly a hafnium-based high-k dielectric.