软钎焊、软銲（soldering）是一种利用熔化熔点较低金属来链接其他金属工件的制造过程。被熔化的金属一般称为銲料，一般其熔点低于摄氏400度。

软钎焊和硬钎焊的差异是在于焊料的熔点，硬钎焊焊料的熔点高于摄氏400度。软钎焊也和焊接不同，软钎焊时不需熔化金属工件。在软钎焊过程中，直接在要链接的部份加热，使焊料融化，因着毛细现象而流到接合处，由于浸润作用和工件结合。一般来言，在冷却后，接点的强度会比工件本身的强度低，不过还是有相当的强度、导电性及防水性。像电子零件和印刷电路板都是用软钎焊的方式接合。

Soldering (pronounced /ˈsɒ ˌdər ɪŋ/ by Americans and as spelt in the UK), is a process in which two or more items (usually metal) are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Soldering differs from welding in that soldering does not involve melting the work pieces. In brazing, the filler metal melts at a higher temperature, but the work piece metal does not melt. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.