This study aimed to compare the between-session reliability of performance and asymmetry variables between unilateral and bilateral standing broad jumps (SBJ). Twenty-four amateur basketball players (12 males and females) completed two identical sessions which consisted of four unilateral SBJs (two with each leg) and two bilateral SBJs. Mean and peak values of force, velocity and power, and impulse were obtained separately for each leg using a dual force platform. Inter-limb asymmetries were computed using the standard percentage difference for the unilateral SBJ, and the bilateral asymmetry index-1 for the bilateral SBJ. All performance variables generally presented an acceptable absolute reliability for both SBJs (CV range = 3.65-9.81%) with some exceptions for mean force, mean power, and peak power obtained with both legs (CV range = 10.00-15.46%). Three out of 14 variables were obtained with higher reliability during the unilateral SBJ (CV_ratio ≥ 1.18), and 5 out of 14 during the bilateral SBJ (CV_ratio ≥ 1.27). Asymmetry variables always showed unacceptable reliability (ICC_range = -0.40 to 0.58), and slight to fair levels of agreement in their direction (Kappa range = -0.12 to 0.40) except for unilateral SBJ peak velocity [Kappa = 0.52] and bilateral SBJ peak power [Kappa = 0.51]) that showed moderate agreement for both SBJs. These results highlight that single-leg performance variables can be generally obtained with acceptable reliability regardless of the SBJ variant, but the reliability of the inter-limb asymmetries in the conditions examined in the present study is unacceptable to track individual changes in performance.

• The between-session reliability of the different single-leg performance variables obtained from the standing broad jump seems to be variant-dependent.

• The unilateral standing broad jump variant could be more reliable test to quantify the single-leg force production, while the bilateral standing broad jump variant is a more reliable alternative to measure the single-leg performance of velocity, power, or impulse.

• The asymmetry variables present poor reliability during both the unilateral and bilateral standing broad jump variants due to the nature variability of asymmetry direction.