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Objective Neck flexion weakness is often observed in amyotrophic lateral sclerosis (ALS) with advancing disease along with declining respiratory function. Medical Research Council (MRC) scoring and hand-held dynamometry (HHD) may serve as a potential surrogate marker for respiratory dysfunction.Methods Sixty-two ALS patients were prospectively recruited at Brain and Nerve Research Centre. Neck flexion strength using both MRC scoring and HHD, alongside standard respiratory function testing with spirometry (Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), In addition disease onset site and duration with ALSFRS-R was recorded.Results Neck flexion weakness (MRC ≤4) was present in 27% of patients and was associated with significantly reduced FVC (70.0±7.2% vs 86.8±2.4% predicted, P=0.038). HHD measurements demonstrated significant correlation with both FVC (R=0.487, P<0.001) and FEV1 (R=0.465, P<0.001). The association was most prominent with bulbar onset disease (R²=0.673, P=0.002). Notably, neck flexion weakness was a significant predictor of FVC ≤50% predicted (Chi²=7.68, P=0.006), a threshold indicating need for ventilatory support.Conclusion Neck flexion weakness, particularly when quantified by HHD, serves as a reliable surrogate marker for respiratory dysfunction in ALS patients. This simple bedside assessment could alert the treating clinician of the impending need for ventilatory support. This enhances the clinical assessment in resource-limited settings or in patients with bulbar dysfunction who struggle with formal spirometry.