Any process that stops, prevents, or reduces the frequency, rate or extent of the phosphorylation of a serine residue of a STAT (Signal Transducer and Activator of Transcription) protein.
synonyms:
GO:1903262,
down regulation of serine phosphorylation of STAT3 protein,
inhibition of serine phosphorylation of STAT3 protein,
downregulation of serine phosphorylation of STAT3 protein,
negative regulation of serine phosphorylation of STAT3 protein,
down-regulation of serine phosphorylation of STAT3 protein
