Aluminum (Al) is an environmental xenobiotic that stimulates free radical generation and hence reproductive toxicity. Coenzyme Q10 (CoQ10) effectively counteracts free radical-induced tissue damage. Omega-3 polyunsaturated fatty acids present in fish oil (FO) exert beneficial effects on reproduction in male animals. This study therefore investigated the effects of both agents on testicular dysfunction induced by aluminum chloride (AlCl3). Fifty male rats were gavaged with either 1% gum acacia (control group) or AlCl3 (34 mg/kg/day) for ten weeks. Concurrently, AlCl3-treated rats received no treatment, CoQ10 (10 mg/kg/day, p.o.), and/or FO (400 mg/kg/day, p.o.) for ten weeks. AlCl3 caused a significant decrease in serum testosterone, luteinizing hormone (LH), and follicular stimulating hormone (FSH), as well as testicular weight, antioxidant enzyme gene expression and activities, reduced glutathione, zinc, adenosine 3',5'-cyclic monophosphate (cAMP) contents, and number of Leydig cells, along with down-regulation of 3beta-hydroxysteroid dehydrogenase (3β-HSD), 17β-HSD, steroidogenic acute regulatory protein (STAR), and cholesterol side-chain cleavage enzyme (P450scc) gene expression. However, testicular Al, malondialdehyde (MDA), and nitric oxide (NO) levels were markedly increased. Treatment with CoQ10 and FO, alone or in combined form led to an improvement in the aforementioned biomarkers. Overall, individual or combined treatment with CoQ10 and FO could ameliorate the toxic effects of AlCl3 on testicular tissues by mechanisms related to their potent antioxidant potential and stimulatory effects on steroidogenic enzymes transcription. CoQ10 seems to be better than FO regarding oxidative and nitrosative stress, Zn deficiency, and Al overload. However, FO showed more pronounced effect than CoQ10 on hormones, steroidogenic markers, and cAMP. A cocktail of both demonstrated greater protective effects on testicular tissues than monotherapy.