Pistachio (PW, Pistacia vera L.) wastes are a collection of favorite materials that are produced in the pistachio processing factories, in combination with its industry derivatives of clusters, soft hull, leaves, hard shell, and kernel. Two experiments were carried out; in the 1st one, the chemical and mineral compositions, in vitro ruminal-digestive fermentation activities, and buffering capacity parameters were determined for PW and its derivatives. For the 2nd experiment, the nutritional effects of an aluminosilicate (AS) and polyethylene glycol (PEG), at 10 g/kg dietary dry matter (DM), on PW-based diets were investigated. However, forty Mahabadi male goat kids 5 months, 22 ± 2.0 kg body weight (BW) were randomly divided into the four experimental diets: control (a basal diet without PW); PW (replaced 40 % of control ingredients with PW); PW + PEG (PW diet + 10 g PEG/kg DM); and PW + AS (PW diet + 10 g AS/kg DM). Crude protein content, dry matter digestibility (DMD), gas production, and metabolizable energy were increased (P < 0.001) in kernel rather than other treatments. Hard shell exhibited the lowest (P < 0.001) DMD and/or organic matter digestibility (at 24 and 96 h), and highest (P < 0.001) neutral detergent fiber, acid detergent fiber, and iron concentrations. In leaves, total phenolic and tannins, calcium, magnesium, and manganese had the highest (P < 0.001) concentrations versus other PW derivatives. Soft hull has the greatest (P < 0.001) acid-base buffering capacity among the evaluated derivatives. Dietary supplementation with 40 % PW decreased (P < 0.001) dry matter intake, final BW, average daily gain, nutrient digestibility, ruminal total volatile fatty acids, propionate, and acetate, but with an increase (P < 0.001) in those parameters in PW + PEG and PW + AS diets. Blood urea nitrogen and total protein decreased (P < 0.05) by dietary PW. The inclusion of 40 % PW in the diet reduced the growth performance and diet nutritive value, but improved plasma antioxidant status (total antioxidant capacity: and malondialdehyde). Addition of PW in goat kids’ diets with PEG or AS improved the digestibility and ruminal fermentation activities and enhanced growth performance. In conclusion, it is recommended to use PW at the dietary level of 40 % in fattening goat kids, provided that it is accompanied by adding AS or PEG to the diet. •Nutritive value of pistachio wastes (PW) and its derivatives was evaluated in vitro and in vivo.•In vitro fermentation of the PW kernel was nutritionally superior to other derivatives.•Dietary inclusion with 40 % PW adversely affected growth performance, digestibility and ruminal activities of goat kids.•Plasma total antioxidant capacity increased and malondialdehyde decreased with dietary 40 % PW inclusion.•Addition of polyethylene glycol or aluminum silicates at 10 g mitigate the adverse effects of PW in kids’ diet.