The aim of the present study was to examine whether loneliness and friendship quality are bidirectionally associated with one another over time. Based on the Evolutionary Theory of Loneliness (Cacioppo & Cacioppo, 2018) and the classical definition of loneliness (Peplau & Perlman, 1982), such a bidirectional association would be expected, but empirical research in this regard is limited. We used data from 615 adolescents (Mage = 10.77 years at Wave 1; 53.5% girls) in a three-wave longitudinal study with one-year intervals between successive measurement waves. Loneliness was measured using the peer-related loneliness subscale of the Loneliness and Aloneness Scale for Children and Adolescents. Friendship quality was measured using the help and closeness subscales of the Friendship Qualities Scale. To test our hypothesis we estimated a cross-lagged panel model. Higher friendship quality was associated with lower levels of concurrent loneliness, which is in line with findings of previous research. However, no significant across-time predictions were found between the two constructs. Hence, using a sample of early adolescents, we could not provide evidence supporting important aspects of the aforementioned loneliness theories.