A thermosiphon cooling assembly for dissipating heat generated by an electronic device includes a housing having a housing top, housing bottom and opposing sides. The opposing sides extend between the housing top and the housing bottom to define a low profile entrance and a low profile exit. A refrigerant is disposed within one or more boiling chambers. Heat generated by the electronic device is transferred to the refrigerant by the boiling chambers for liquid-to-vapor transformation. Condenser tubes having a bottom end and a top end extend from the boiling chambers at a diagonally upward angle across the sides between the housing bottom and housing top. The condenser tubes receive and condense vapor boiled off from the refrigerant. Air moving devices axially move air through the housing. Air is flowed across the condenser tubes to facilitate condensation.