Little (or Small) Vespers is a shortened form of vespers, performed (typically in monasteries) in advance of a vigil service. It is normally preceded by the Ninth Hour, and usually followed by supper. The all-night vigil then follows at the appointed time.
Outline of Little Vespers
Opening prayers [shortened, as at vespers, when 9th hour precedes]
Psalm 103(104); Glory ... Now ... Alleluia ... (etc.)
Reader: Lord have mercy (3) Glory ... Now ...
Lord, I Call (on 4) : glory and now : theotokion or festal sticheron
O Gladsome Light
Vouchsafe, O Lord
Aposticha; glory and now: theotokion or festal sticheron
Song of Symeon
Troparion; [glory and now: theotokion]
Litany (as at beginning of matins): Have mercy on us ...
Priest: Glory to You ...
Choir: Glory ... (etc.) ... Bless.
Small dismissal by priest
1) The usual litanies from vespers are omitted.
2) The short litany from the beginning of matins (before the Six Psalms), is chanted just before the end
3) No psalter readings, lessons, or entrance.
4) Lord, I Call is sung on 4.
5) The prokeimenon of the day is as usual, but if little vespers precedes a resurrectional vigil (that is, on Saturday) the prokeimenon "The Lord is King" is in Tone 4, and only 1 verse (not 3) is used with it, namely: "He has clothed himself with majesty and has girded himself."