<p>ALL is recognised as a heterogeneous malignancy affecting lymphocyte precursors. Considering shortcomings of the current treatments, herbal compounds have always been in the focus of attention as novel anticancer candidates, owing to their main advantages like promising levels of bioactivity and toxicity. Accordingly, the anticancer potentials of gamma-terpinene were evaluated on cell-death relevant proteins as well as on Nalm-6 ALL cells alone and in combination with Doxorubicin (Dox). In this study, an optimized form of GT from the RCSB PDB structure databank was docked to Bcl-2 and p21 proteins using MOE software. Nalm-6 cell viability in exposure to GT was measured using dye-exclusion and MTT methods. Initiation of apoptosis was also studied by Annexin-V/PI DNA-staining kit. In addition, cellular mRNA levels of genes coding for hTERT, Bcl-2, Bax, P53, and P21 were quantified and detected by the real-time PCR method. The differences were assessed using SPSS version 26 and statistical data analysis was done by ANOVA (one-way). Dockability of GT in the active cavities of Bcl-2 and P21 was evident, involving at least 11 interacting amino acids. Also, GT exerted dose-dependent cytotoxicity on Nalm-6 cells, exhibiting the IC₅₀ of 27.6 (mM) and selectivity index (SI) of 4.58 in comparison with exposure to PBMC normal cells. Bax, P53 and P21 gene mRNAs were at higher titres in exposure to GT, while the GT-treated cells displayed lower levels of Bcl-2 gene. When applied in combination, GT (10 mM) enhanced the cytotoxicity of Dox (8 nM) against Nalm-6 cells significantly (p &gt; 0.05). Molecular docking, cellular studies, and gene expression analyses suggested that GT possesses promising antileukemic potential on Nalm-6 cells at reasonable selectivity over normal blood cells. However, further investigations, including studies targeting protein level and in vivo validations, are necessary to further proof drugability of this monoterpene product.</p>