Research has shown worker loneliness to be associated with a lower level of job performance and other undesirable outcomes. Recently, researchers have called for studies of the possible causes of feelings of isolation (i.e., workplace loneliness). Our study addresses these calls for research. Building upon the theoretical framework of Wright and Silard (2021), we examined seven theory-based predictors of feelings of isolation (six of which had not been examined in previous research). Using data from a sample of 244 telecommuters and their supervisors, we found support for five of the seven relationships we hypothesized. Specifically, we found feelings of isolation to be negatively related to whether individuals had a choice whether to telecommute and the length of the supervisor-telecommuter relationship. We found reports of feeling isolated to be positively associated with a telecommuter's need for affiliation, the extent of telecommuting, and the distance a telecommuter lived from the central workplace. As hypothesized, we also found telecommuter feelings of isolation were negatively related to telecommuter performance and job satisfaction. The results of our study suggest several factors employers should consider in making decisions about telecommuting arrangements.