In a 42-day study, 195 growing pigs (Landrace × Yorkshire × Duroc) weighing 23.83 ± 1.95 kg were randomly divided into three treatments, each with 13 replicates and 5 pigs (3 barrows and 2 gilts) per pen. The treatments were control (CON)—basal diet, and basal diet with 3% and 6% almond hull as treatment (TRT) 1 and 2, respectively. The results show a significant increase (p < 0.05) in average daily gain (ADG) and average daily feed intake (ADFI) for both treatment 1 and treatment 2 by week 6 when compared to the control group. This improvement in ADG and ADFI exhibits a consistent trend (p < 0.10) throughout the overall trial period in comparison to the control group. Additionally, there is a tendency for enhanced gain-to-feed ratio (G:F) at the end of week 6 (p < 0.10) in comparison to the control group and remained constant (p > 0.05). No significant impact (p > 0.05) on nutrient digestibility and fecal microbiota was observed. However, NH₃ gas showed a tendency to decrease (p < 0.10). Results suggested that almond hulls could improve growth and reduce ammonia gas without adverse effects on digestion, microbiota, and fecal score.