Leo Minor was not regarded as a separate constellation by classical astronomers; it was designated by Johannes Hevelius in 1687.

The constellation also includes two stars with planetary systems, two pairs of interacting galaxies, and Hanny's Voorwerp, a unique deep-sky object.

[3] Johannes Hevelius first depicted Leo Minor in 1687 when he outlined ten new constellations in his star atlas Firmamentum Sobiescianum,[4] and included 18 of its objects in the accompanying Catalogus Stellarum Fixarum.

[6] In 1845, English astronomer Francis Baily revised the catalogue of Hevelius's new constellations, and assigned a Greek letter known as Bayer designation to stars brighter than apparent magnitude 4.5.

[8] German astronomer Christian Ludwig Ideler posited that the stars of Leo Minor had been termed Al Thibā' wa-Aulāduhā "Gazelle with her Young" on a 13th-century Arabic celestial globe, recovered by Cardinal Stefano Borgia and housed in the prelate's museum at Velletri.

[9][10] Arabist Friedrich Wilhelm Lach describes a different view, noting that they had been seen as Al Haud "the Pond", which the Gazelle jumps into.

[11] A dark area of the sky with a triangle of brighter stars just visible to the naked eye in good conditions,[13] Leo Minor has been described by Patrick Moore as having "dubious claims to a separate identity".

[14] It is a small constellation bordered by Ursa Major to the north, Lynx to the west, Leo to the south, and touching the corner of Cancer to the southwest.

[15] The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 16 sides.

[1] Ranked 64th out of 88 constellations in size, Leo Minor covers an area of 232.0 square degrees, or 0.562 per cent of the sky.

[6] At magnitude 3.8, the brightest star in Leo Minor is an orange giant of spectral class K0III named 46 Leonis Minoris or Praecipua;[18] its colour is evident when seen through binoculars.

[6] More confusion occurred with its proper name Praecipua, which appears to have been originally applied to 37 Leonis Minoris in the 1814 Palermo Catalogue of Giuseppe Piazzi, who mistakenly assessed the latter star as the brighter.

Separated by 0.1 to 0.6 second of arc from the primary, the secondary is a yellow-white main sequence star of spectral type F8.

[24] Around 98 light-years (30 parsecs) away and around 10 times as luminous as the Sun, 21 Leonis Minoris is a rapidly rotating white main-sequence star, spinning on its axis in less than 12 hours and very likely flattened in shape.

[26] These are short period (six hours at most) pulsating stars which have been used as standard candles and as subjects to study asteroseismology.

[50] It has tidal filaments and intense star formation, so it was listed in Halton Arp's Atlas of Peculiar Galaxies.

[51] NGC 3003, a SBbc barred spiral galaxy with an apparent magnitude of 12.3 and an angular size of 5.8 arcminutes, is seen almost edge-on.

[63] The voorwerp is thought to be the visual light echo of a quasar now gone inactive,[64] possibly as recently as 200,000 years ago.