剪刀，古称铰剪或铰刀，粤语称铰剪，闽语称铰刀，是一种剪裁对象的工具，有双刀刃。

剪刀是约西元前1500年时由古埃及人发明的，最早在古埃及人的废墟中找到，这些剪刀是用一种金属制成的（不像现在是以一个中心点固定于两片交叉刀刃的剪刀﹞，现代交叉刀刃的剪刀是由古罗马人所发明的（约于西元100年），早期的剪刀使用于衣服的制造及理发。

剪刀属于简单机械中的杠杆，大部分剪刀是费力杠杆，刀刃属于斜面。

它常用于剪裁头发、布料、纸及食物等，医生进行手术亦有使用。中国的剪纸艺术便是靠一把剪刀和纸的配合而成。

在未有剪刀前，人类需要用火来烧短毛发。

Scissors are hand-operated shearing tools. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles (bows) opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, cloth, rope, and wire. A large variety of scissors and shears all exist for specialized purposes. Hair-cutting shears and kitchen shears are functionally equivalent to scissors, but the larger implements tend to be called shears. Hair-cutting shears have specific blade angles ideal for cutting hair. Using the incorrect scissors to cut hair will result in increased damage or split ends, or both, by breaking the hair. Kitchen shears, also known as kitchen scissors, are for cutting and trimming foods such as meats.