The noise influence to speech signal waveform can be characterized by reduced speech dynamic range (rDR). This motivated the present work to propose an rDR-based intelligibility measure (denoted as rDRm) that could be used to non-intrusively (i.e., do not require clean reference speech signal) predict speech intelligibility in noise and is computed only using the dynamic range extracted from the noise-corrupted speech. The rDRm indices were evaluated with intelligibility scores obtained from normal-hearing listeners presented with sentences corrupted by four types of maskers in a total of 22 conditions. High correlation (r=0.93) was obtained between rDRm values and listeners’ sentence recognition scores, and this correlation was comparable to those computed with existing intrusive and non-intrusive intelligibility measures. This suggests that the dynamic range of speech signal may work as a simple but efficient predictor of speech intelligibility in noise, whose computation does not need access to the clean reference speech signal.