The objective of the present work is to study the effect of minimum quantity lubrication (MQL) on the performance of helical milling for machining high-quality holes with a small-diameter tool. Helical milling with small tools (diameter < 5 mm) has been a challenging domain due to the problem of tool deflection, which deteriorates the hole quality and adversely affects the process efficiency. In this study, helical milling of stainless steel (SS 304) is carried to machine holes using a 3 mm diameter coated carbide tool in minimum quantity lubrication (MQL), and the performance is compared with dry and conventional flood cooling based on the hole quality and tool wear. The findings of this study reveal that MQL results in high-quality holes with the least circularity and cylindricity errors compared to dry and flood lubrication. Surface morphology study of the machined holes shows that the holes generated in MQL have smoother surfaces with no evidence of severe surface defects. MQL can also significantly mitigate the problem of tool deflection encountered in small-diameter tools and reduce tool wear by 33.3% and 21.7% compared to dry and flood lubrication, respectively. As per ISO 286-2 standard, hole quality up to grade H8 is achieved with MQL, while dry condition and flood lubrication yield hole quality corresponding to H9 grade. This study concludes that MQL-assisted helical milling is one of the sustainable alternatives for the production of high-quality small-diameter holes in stainless steel.