Polyethylene blend compositions suitable for injection molding, injection molded articles, and processes for injection molding articles are provided. The polyethylene compositions include a first polyethylene having a melt index of 0.1 to 3.0 g/10 min and a density of from 0.905 to 0.938 g/cm.sup.3; and a second polyethylene having a melt index of 10 to 500 g/10 min and a density of 0.945 to 0.975 g/cm.sup.3. The compositions have a density of from 0.920 to 0.973 g/cm.sup.3 and a melt index of 2 to 200 g/10 min, and the density of the second polyethylene is from 0.037 to 0.062 g/cm.sup.3 greater than the density of the first polyethylene. The compositions exhibit improved physical properties, such as Environmental Stress Crack Resistance, relative to conventional compositions of similar melt index and density. In certain embodiments, the compositions, and articles produced therefrom, also exhibit an improved balance of toughness properties and processability properties.