HTT may refer to:
- Homotopy type theory, in mathematical logic and computer science
- Hybrid turbocharger, an electric turbocharger that eliminates turbo lag and reduces vehicle emissions
- Human Terrain Team, a program of the US military, or a team in this program
- Huntingtin, a gene (HTT) or protein (Htt), which are causal to Huntington's Disease
- Hyper-Threading Technology, Intel's trademark for their implementation of the simultaneous multithreading technology on the Pentium 4 and later microarchitecture
- HyperTransport Technology, a bidirectional serial/parallel high-bandwidth, low-latency point to point link used by AMD
- Ho-kago Tea Time, a musical band in a manga K-On!, as well as anime and game based thereon