Abstract Introduction Mucosa‐associated lymphoid tissue 1 (MALT1) modulates T helper cell differentiation, pro‐inflammatory cytokine production, and epidermal hyperplasia to participate in the pathology of psoriasis. This study aimed to explore the correlation of blood MALT1 with treatment outcomes in psoriasis patients. Methods MALT1 was detected in peripheral blood mononuclear cells by reverse transcription‐quantitative polymerase chain reaction in 210 psoriasis patients before starting or converting to a new therapy, 50 disease controls, and 50 healthy controls. The psoriasis area severity index (PASI) score was evaluated at month (M)1, M3, and M6 in psoriasis patients. Results MALT1 was increased in psoriasis patients versus disease controls and healthy controls (both p