This study aimed to analyze the differences in root traits of two wheat cultivars and their relationship with phosphorus (P) acquisition in a soil with low P availability. For that, biomass production, root morphology, acid phosphatase activity, carboxylate exudation, and arbuscular mycorrhizal colonization were examined in “TCRB14” and “STKI14” wheat cultivars grown in pots. Biomass production was highly correlated with P acquisition and was greater in TCRB14. Mycorrhizal colonization and oxalate concentration in rhizosphere soils were also greater in TCRB14. STKI14 presented higher acid phosphatase activity in their rhizosphere, although not significantly. Overall, TCRB14 showed longer, larger, more branched, and thinner root systems, directly correlating with P acquisition. In this study, morphological root traits were the predominant component of P acquisition and, along with AM symbiosis and oxalate exudation, could comprise key targets for breeding programs orientated to more sustainable agricultural production under P-restricted scenarios.