Background <p>Epoxies are a family of glassy polymers which are widely used as adhesives, encapsulants, and composite matrix materials.</p> Objective <p>In this technical note, we examined the stress-strain response of Epon 828/DEA epoxy at temperatures ranging from room temperature to above the glass transition temperature.</p> Methods <p>In particular, the true stress-strain behavior at the reduced center of each specimen was estimated from digital image correlation and the deformation and stress state were compared to those from finite element analysis.</p> Results <p>The results suggested excellent repeatability based on multiple tests at each temperature and when compared to previous studies at a common temperature. Moreover, it was found that the material exhibited a constant ratio of bulk and shear response, a post-yield decrease in stress by a factor of approximately one-third, and a flat plastic plateau out through a strain of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\epsilon _{log}\approx 0.45\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>ϵ</mi> <mrow> <mi mathvariant="italic">log</mi> </mrow> </msub> <mo>≈</mo> <mn>0.45</mn> </mrow> </math></EquationSource> </InlineEquation> up to temperatures of 55 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(^{\circ }\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C.</p> Conclusions <p>The data indicate that the interfacial fracture toughness trends in previous work are broadly valid below the glass transition.</p>