A thermally conductive silicone gel composition, comprising: an organopolysiloxane, A, having two or more alkenyl groups per molecule; an organohydrogenpolysiloxane, B, having two or more hydrogen atoms bonded directly to silicon atoms; a platinum group metal-containing curing catalyst, C, in a catalytic amount; and aluminum hydroxide particles, D, as thermally conductive particles in an amount of 200 to 600 parts by mass with respect to 100 parts by mass of a total amount of the components A to C, the aluminum hydroxide particles comprising, based on 100% by mass of the aluminum hydroxide particles, aluminum hydroxide particles, D-1, having a median diameter, D50, of 30 μm or more in an amount of more than 45% by mass and less than 75% by mass; and aluminum hydroxide particles, D-2, having a median diameter, D50, of less than 30 μm in an amount of 25% by mass or more and 55% by mass or less, the median diameter, D50, being a particle diameter at 50% in a volume based cumulative particle size distribution, which is determined by a particle size distribution measurement according to a laser diffraction scattering method, wherein the thermally conductive silicone gel composition is free from alumina particles, crystalline silica particles, and magnesium oxide particles, and the thermally conductive silicone gel composition has a relative dielectric constant of 5.0 or less at a frequency of 1 MHz according to a mutual induction bridge method of JIS K 6911: 2006 and has a Shore OO hardness of 5 to 60 according to ASTM D2240 measured by an automatic durometer stand using a stack of four 3 mm thick sheets of the thermally conductive silicone gel composition. an organopolysiloxane, A, having two or more alkenyl groups per molecule; an organohydrogenpolysiloxane, B, having two or more hydrogen atoms bonded directly to silicon atoms; a platinum group metal-containing curing catalyst, C, in a catalytic amount; and aluminum hydroxide particles, D, as thermally conductive particles in an amount of 200 to 600 parts by mass with respect to 100 parts by mass of a total amount of the components A to C, the aluminum hydroxide particles comprising, based on 100% by mass of the aluminum hydroxide particles, aluminum hydroxide particles, D-1, having a median diameter, D50, of 30 μm or more in an amount of more than 45% by mass and less than 75% by mass; and aluminum hydroxide particles, D-2, having a median diameter, D50, of less than 30 μm in an amount of 25% by mass or more and 55% by mass or less, the median diameter, D50, being a particle diameter at 50% in a volume based cumulative particle size distribution, which is determined by a particle size distribution measurement according to a laser diffraction scattering method, wherein the thermally conductive silicone gel composition is free from alumina particles, crystalline silica particles, and magnesium oxide particles, and the thermally conductive silicone gel composition has a relative dielectric constant of 5.0 or less at a frequency of 1 MHz according to a mutual induction bridge method of JIS K 6911: 2006 and has a Shore OO hardness of 5 to 60 according to ASTM D2240 measured by an automatic durometer stand using a stack of four 3 mm thick sheets of the thermally conductive silicone gel composition.