<p>Live weight (LW) prediction equations provide a viable alternative to commercial scales. This study aimed to predict the live weight of Pelibuey ewes based on body volume (BV) using linear, multiple linear, and non-linear models. A dataset comprising body length (BL), chest girth (CG), and LW from 357 Pelibuey ewes up to two years of age was analyzed. BV was calculated using the cylinder formula, and Pearson’s correlation analysis was conducted to assess the relationship between LW and BV. Linear, quadratic, cubic, multiple linear, exponential 2P, exponential 3P, Gompertz 3P, Gompertz 4P and Modified Wood regression models were fitted to derive LW prediction equations from BV. BV showed a significant positive correlation with LW (<i>r</i> = 0.80). The best-fitting models included linear, quadratic, cubic, and non-linear equations using BV as a predictor, as well as a multiple linear equation incorporating both BV and BL, with coefficients of determination (R² or Pseudo R²) ranging from 0.63 to 0.64. In the validation process, the multiple linear model LW = 13.445 + 0.949(BV) − 0.132(BL) demonstrated the highest accuracy. These findings indicate that, regardless of the mathematical model used, BV is a more reliable predictor of LW in Pelibuey ewes than CG or BL while increasing the number of parameters in the exponential and Gompertz models did not lead to improved accuracy. The simple linear regression equation LW = 6.643 + 0.880(BV) is recommended for its ease of use in predicting live weight of Pelibuey ewes.</p>