卷积码（convolution code）是频道编码(channel coding)技术的一种，在电信领域中，属于一种错误更正码(error-correcting code)。相对于分组码，卷积码维持频道的记忆效应(memory property)。卷积码的由来，是因为输入的原始消息数据会和编码器(encoder)的脉冲响应(impulse response)做卷积运算。卷积码具有以下特性：

In telecommunication, a convolutional code is a type of error-correcting code that generates parity symbols via the sliding application of a boolean polynomial function to a data stream. The sliding application represents the 'convolution' of the encoder over the data, which gives rise to the term 'convolutional coding.' The sliding nature of the convolutional codes facilitates trellis decoding using a time-invariant trellis. Time invariant trellis decoding allows convolutional codes to be maximum-likelihood soft-decision decoded with reasonable complexity.