This research work aims to represent the renovations in the physical and mechanical properties of nano-hydroxyapatites (nHAPs) filled dental restorative composite (DRCs). The concept of adhesive bonding has revolutionized adhesive dentistry. New or upgraded products are constantly being evolved with enhanced properties over their forebears and being introduced in the market. To achieve better interfacial strength and evaluate the effect of coupling agents, nano-hydroxyapatites particles were surface functionalizes with two different coupling agents (namely (3-methacryloxypropyl) trimethoxy silane (MPTS) and (3-aminopropyl) triethoxysilane (APTES). These nanoparticles were used in the formulation of high strength, photo-curable DRCs with varying the wt. % (0, 4, 8 and 12) of functionalized nHAPs. The matrix of the DRCs consists of bisphenol A-glycidyl methacrylate (Bis-GMA) as a base monomer and Tri-ethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl-methacrylate (HEMA) were used as a diluent monomer. The experimental investigations indicate that void contents and depth of cure of the composite shows the increasing trend with an increase in the functionalized filler particles. Hardness and compressive strength of the DRCs were improved by 39.52% for 12 wt.% MPTS treated (12 M) and 29.33% for 8 wt.% APTES treated (8 A) fillers respectively. However, the Flexural strength of the composite decreases with increases in the filler amount from 173.76 MPa to 122.84 MPa and further up to 83.63 MPa, but still this value is higher than that of an acceptable limit of flexural strength for dentistry (i.e. 74.2 MPa). Since it can be concluded that functionalized nHAPs filled dental composite is a promising material and has the potential to become a successful substitute for restorative dentistry.