Curable composition and cured material

A curable composition, comprising:

• a compound (A) having one (meth)acrylate group in one molecule;
• a compound (B) having two or more (meth)acrylate groups in one molecule;
• a polymerization initiator (C);
• a dispersant (D);
• and
• a thermally conductive filler (E) containing magnesium oxide,
• wherein the dispersant (D) comprises at least one compound selected from the group consisting of a polyglycerin monoalkyl ether compound, a compound having a carboxy group, and a metallic soap,
• wherein a content of the dispersant (D) is from 1.5 parts by mass to 3 parts by mass with respect to 100 parts by mass of the compound (A),
• wherein the thermally conductive filler (E) further contains zinc oxide,
• wherein when the thermally conductive filler (E) contains a compound other than the magnesium oxide and the zinc oxide, the content of the compound other than the magnesium oxide and the zinc oxide is 10% by mass or less relative to the total mass of the thermally conductive filler (E),
• wherein a content of the magnesium oxide with respect to a total mass of the thermally conductive filler (E) is from 10% by mass to 70% by mass.