The only two planets in our solar system that do not have moons are Mercury and Venus.
Also known as a moon, a natural satellite is an astronomical object that orbits another celestial body such as a planet. In total, there are more than 190 known natural satellites. Of the eight planets in the solar system, six of them have natural satellites while two of them do not. These two planets are Mercury and Venus, which, incidentally, are the two planets closest to the sun. Outside of the eight planets, there are some dwarf planets, such as Pluto and Eris, that also have natural satellites.
Mercury is the first planet from the sun in the solar system as well as the smallest planet among the eight planets. Named after the Roman god Mercury, the planet also has the shortest orbital period around the sun due to its closeness to the sun. As stated earlier, the planet does not have any known natural satellites due to a number of reasons.
Just like Mercury, Venus also does not have any known natural satellites. Venus is the second innermost planet from the sun in the solar system. The planet has an orbital period of about 243 days although its orbital direction is unlike most of the other planets.