Cardiovascular diseases are the leading causes of morbidity and mortality. Overweight, obesity, and accelerated growth during early childhood have been associated with adverse cardiovascular outcomes in later life. Few studies have assessed whether trajectories of accelerated growth in early childhood are associated with preclinical cardiovascular measurements. We aimed to evaluate the associations between childhood body mass index (BMI) growth trajectories and measures of macro- and microvascular function in early adolescence. Measurements of macrovascular function (systolic and diastolic blood pressure (SBP and DBP), pulse wave velocity (PWV), and microvascular function (central retinal arteriolar/veinular equivalent) were assessed at 11 years old in a Spanish birth cohort study (n = 489). BMI trajectories from birth to 9 years were identified using latent class growth analysis. Multiple linear regression assessed the associations between the BMI trajectories and macro- and microvascular function. Compared to children with average birth size and slower BMI gain (reference), children with a lower birth size and accelerated BMI gain had increased SBP [β = 6.57; (95% CI 4.00, 9.15)], DBP [β = 3.65; (95% CI 1.45, 5.86)], and PWV [β = 0.14; (95% CI 0.01, 0.27)]. Children with higher birth size and accelerated BMI gain had increased SBP [β = 4.75; (95% CI 1.79, 7.71) compared to the reference. No significant associations between BMI trajectories and the microvascular measurements were observed. In conclusion, we found that childhood BMI trajectories characterized by accelerated growth are associated with preclinical macrovascular measurements in young adolescents.