小塔螺科（学名：Pyramidellidae），亦作尖塔螺科或简单只叫塔螺科，是软体动物门腹足纲下的一个科。旧属肠纽目（Heterostropha，又译异旋目），成员主要是营寄生生活的小型海螺。
小塔螺科的物种分布于整个世界，有超过六千个不同的物种，合组成超过350个属与亚属。由于本科物种皆属于微小贝，相关研究少，物种间支序亲缘关系（英语：phylogenetic）并不十分清楚，大众对于各物种的归属也没有共识。举例说：单单是 Schander (1999) 就列出了超过300个属级以上的分类单元命名，并将这些分类单元整理。由于近年本科在世界各地各个属的分类未再有可一般化的修订，这个科内各个分类单元仍然保持是多系群，也就是说这些分类的混乱还有一段时间。然而，从整个科来看仍然是个单系群。
本科物种主要分为11个亚科（Ponder & Lindberg 1997）。An alternative interpretation is that the family Pyramidellidae is but one of six families within the superfamily Pyramidelloidea (Schander, van Aartsen & Corgan 1999). 当中有不少罕见或不常纪录的物种。
本科之下的亚科在不同年代刊行的分类学文献都有所不同，当中最为普遍的分类是2005年的布歇特和洛克罗伊的腹足类分类。以下详列自1997年以来多个分类间的差异。
在1997年的旁得和林德伯格的腹足类分类，本科的分类如下：
Taxonomy of Pyramidellidae by Schander, Van Aartsen & Corgan (1999):
在2005年《布歇特和洛克罗伊的腹足类分类》，原来小塔螺总科之下的各科均被降级成为新的小塔螺科的亚科；而各科之下的亚科亦变成了各个亚科之下的族。这些变更总结如下：
2010年，本科得到确认为单系群。
2017年，栖息于中南太平洋深海的塔螺总科新属属 Peñas & Rolán, 2017得到确认。
截至2018年7月9日 (2018-07-09)，WoRMS纪录小塔螺科包括下列各亚科与族：
The following genera are currently difficult to place within existing subtaxa of the Pyramidellidae.
The following species is of uncertain placement within Pyramidellidae.
下列为本科分类单元的异名：
本物种有世界性分布，但当中不少物种都只在相当细小范围内分布。在佛得角的各物种均为当地的特有种。
The length of the slender, elongated (turreted or conical) shells varies between 0.5 mm and 3.5 cm, but most species in the family have shells which are smaller than 13 mm.
The texture of these shells is smooth or sculptured in various forms such as ribs and spirals. Their color is mostly white, cream or yellowish, sometimes with red or brown lines.
The shell of these snails has a blunt, heterostrophic (i.e. whorls appear to be coiled in the opposite direction to those of the teleoconch) protoconch, which is often pointed sideways or wrapped up. The teleoconch is dextrally coiled, but the larval shells are sinistral. This results in a sinistrally coiled protoconch.
The columella has usually one, but sometimes several, spiral folds. The aperture is closed by an operculum.
The operculum is ovoid and paucispiral, with the apex anterior, a thread-like arcuate ridge on the proximal side, the inner margin notched in harmony with the plaits of the pillar when prominent.
The Pyramidellidae are ectoparasites, feeding mainly on other molluscs and on annelid worms, but some are known to feed on peanut worms and crustaceans.A few species in the family Pyramidellidae, such as , are symbiotic with sea anemones, such as .
They do not have a radula. Instead their long proboscis is used to pierce the skin of its prey and suck up its fluids and soft tissues. The eyes on the grooved tentacles are situated toward the base of the tentacles. These tentacles have a concave surface. Between the head and the propodium (the foremost division of the foot), a lobed process called the mentum (= thin projection) is visible. This mentum is slightly indented in midline.
These gastropods are hermaphrodites, laying eggs in jelly-like masses on the shell of its host. Some species have spermatophores.
本科的学名源于金字塔的英语，而这亦是这些物种普遍的外型。准确点说：这些物种都呈正圆锥体的模样，又或是正多边形的锥体。
