The most frequently heard vocalizations of Blue-necked Tanager are calls, which variously are described as "weak chips and a seep" (Hilty and Brown 1986, Hilty 2003) or as "a high tsit, rich tchup, and ti" (Lane, in Schulenberg et al. 2007). Isler and Isler (1987) give a more complete description of calls of Blue-necked Tanager: a complaining Moderate-pitched che and a High-pitched seet. Gives notes singly or repeats the che in rapid series that may end with a louder chep or seep". Sick (1993) also described a call that is reminiscent of calls of a siskin (Spinus), tsiBIT-tsi-BIT. Blue-necked Tanager calls frequently when foraging (Isler and Isler 1987).
A vocalization that is believed to be the song is described as "a rapid series of chittery notes followed by several strained, rising notes, e.g., chit-t-t't't't't't't't', suezzz, suezzz, suezzz" (Hilty 2011).