This　study　introduces　transparent　MgO　ceramics　produced　via　simply　vacuum　sintering　at　1200–1500　°C　by　optimal　incorporation　of　MgF2　as　a　sintering　additive.　The　effect　of　MgF2　content　and　sintering　temperature　on　the　densification　process,　optical,　and　thermal　properties　of　MgO　ceramics　is　presented　with　emphasis　on　its　function　as　a　sintering　aid　and　adverse　effect　of　MgF2　evaporation　in　the　condition　of　high　MgF2　content　or　high　sintering　temperature.　MgO　ceramic　with　1.0　mol%　MgF2　sintered　at　1300　°C　exhibits　the　highest　relative　density　of　99.95%　with　average　grain　size　of　17.46　μm.　The　in-line　transmittance　attains　60%　at　1000　nm　and　＞80%　in　the　infrared　range　(3.8–6.8　μm),　without　absorption　bands　originated　from　the　carbon　contamination.　The　corresponding　room-temperature　thermal　conductivity　reaches　47.25　W/(mK).　These　results　demonstrate　that　MgF2　is　an　outstanding　sintering　additive　for　the　preparation　transparent　MgO　ceramics.　©　2023　Elsevier　Ltd　and　Techna　Group　S.r.l.