Using SIMD (Single Instruction Multiple Data) is a costeffective way to explore data parallelism on modern processors. Most processor vendors today provide SIMD engines, such as Altivec/VSX for POWER, SSE/AVX for Intel processors, and NEON for ARM. While high-level SIMD programming models are rapidly evolving, for many SIMD developers, the most effective way to get the performance out of SIMD is still by programming directly via vendorprovided SIMD intrinsics. However, intrinsics programming is both tedious and error-prone, and worst of all, introduces non-portable codes. This paper presents the Generic SIMD Library (https://github.com/genericsimd/generic-simd/), an open-source, portable C++ interface that provides an abstraction of short vectors and overloads most C/C++ operators for short vectors. The library provides several mappings from platform-specific intrinsics to the generic SIMD intrinsic interface so that codes developed based on the library are portable across different SIMD platforms. We have evaluated the library with several applications from the multimedia, data analytics and math domains. Compared with platform-specific intrinsics codes, using Generic SIMD Library results in less line-of-code, a 22% reduction on average, and achieves similar performance as platform-specific intrinsics versions. Copyright © 2014 ACM.