CeVIO is a Japanese singing and speech voice synthesis brand operated by the CeVIO Project, a consortium that includes voice synthesis specialist Techno-Speech, Inc. and publisher Frontier Works. The flagship desktop application, CeVIO Creative Studio, debuted in 2013 and uses HMM-based speech synthesis to produce both sung vocals and spoken dialogue from text input, with parameters for pitch, speed, and intonation. A successor product line, CeVIO AI, replaces the older engine with deep neural network synthesis (DNN/RNN) for more natural timbre and expression, and a sister brand, VoiSona, packages the same underlying technology as a VST-compatible plugin for use inside DAWs.

The platform is built around a roster of branded character voicebanks rather than generic voices. Original mascots include Sato Sasara, Suzuki Tsudumi, and Takahashi, and the catalog has expanded through collaborations with voicebanks tied to BanG Dream!, Kizuna AI, and Kamitsubaki Studio's 'musical isotope' series (KAFU, RIME, and others). The software is positioned in the same market as Yamaha's Vocaloid and Dreamtonics' Synthesizer V, and it is widely used by Japanese producers releasing original songs and covers on platforms like Niconico and YouTube.

CeVIO Creative Studio received the Microsoft Innovation Award 2013 and a CEDEC Award the same year. Releases are Windows-only and the interface is published in Japanese, which has kept the user base concentrated in Japan, though voicebanks and tracks made with the software circulate internationally through the broader vocal-synth community.

CeVIO has 2 products cataloged on Equipboard, including Virtual Instrument.