We investigated pitch perception of string vibrato tones among string players in two separate studies. In both studies we used tones of acoustic instruments (violin and cello) as stimuli. In the first, we asked 192 high school and university string players to listen to a series of tonal pairs: one tone of each pair was performed with vibrato and the other without. Violin tones with vibrato were judged as lower in pitch than non-vibrato stimuli with the same mean frequency, more so among high school string players than university students. In the second study string players tuned their own instrument to match stimulus tones and we tested whether there are differences when performers match tones using vibrato versus non-vibrato. Participants were 30 high school string players and 30 university string players: 20 cellists, 20 violists, and 20 violinists. Performers tuned slightly but significantly lower (about three cents) when using vibrato. This outcome was consistent for tuning conditions, instruments, and experience levels.