A turbine blade includes an airfoil having an internal cooling circuit therein. The airfoil extends from a root to a tip cap, and includes laterally opposite pressure and suction sides extending between a leading edge and an opposite trailing edge over which is flowable a combustion gas. A pair of squealer tips extend radially upwardly from the tip cap along the pressure and suction sides, and are spaced apart between the leading and trailing edges to define an upwardly open tip cavity. At least one of the squealer tips includes a slot extending radially inwardly to the tip cap, with the slot also extending along the squealer tip between the leading and trailing edges. A plurality of spaced apart supply holes extend radially through the tip cap in the slot in flow communication with the cooling circuit for channeling the coolant into the slot for cooling the squealer tip. A thermal barrier coating may then be disposed on an outboard side of the squealer tip for providing insulation against the combustion gas flowable therealong.