转运核糖核酸（Transfer RNA，简称tRNA}}，又称发送核糖核酸、转移核糖核酸，是小RNA分子，能够在转译时，携带特定的氨基酸到正在加上氨基酸的多肽链（polypeptide chain）的ribosomal site上。tRNA能认得特定的密码子，有个能使氨基酸接附在其上的位置。借由反密码子使得每个tRNA能辨识的密码子均不同。（反密码子包含一段与mRNA上一段互补的串行）每个tRNA分子理论上只能与一种氨基酸接附，但是遗传密码有简并性（degeneracy），使得有多于一个以上的tRNA可以跟一种氨基酸接附。

A transfer RNA (abbreviated tRNA and archaically referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that serves as the physical link between the mRNA and the amino acid sequence of proteins. It does this by carrying an amino acid to the protein synthetic machinery of a cell (ribosome) as directed by a three-nucleotide sequence (codon) in a messenger RNA (mRNA). As such, tRNAs are a necessary component of translation, the biological synthesis of new proteins according to the genetic code.