Past research suggests that national narcissism goes hand in hand with negative intergroup and intragroup outcomes. We contend that national narcissism can be also linked to maladaptive intra-individual concomitants. Across two studies, we examined the relationship between national narcissism and loneliness, using representative samples from Poland. Study 1 ( N = 633) demonstrated a positive correlation between national narcissism and loneliness. Study 2 ( N = 811) employed a two-wave design to test bidirectional effect of national narcissism and loneliness. The results confirmed that both cross-lagged paths between national narcissism and loneliness were significant over the 6-month period, reinforcing the findings from Study 1.