Synthetic dyes are not eco-friendly and have negative effects on the skin of the wearer when used to color apparel and textiles. Therefore, it is thought that natural dye is a good substitute for environmentally friendly textile coloration and manufacturing. In the present investigation, we used turmeric (Curcuma longa L.) extract to dye viscose garments. To increase the total uptake of dyes into the innermost regions of the fabric, pre-treatments with natural mordants (derived from Citrus lemon and vinegar) and chemical mordants (Potassium hydroxide and Sodium carbonate) were also conducted. The resultant color-strength (K/S) of the bio-mordanted pre-treatment sample was greater than the chemical mordanted sample by about 228.17%. Colorfastness of rubbing (dry and wet), washing, water, and perspiration (acidic and alkaline) tests were carried out to explore the fastness characteristics of colored fabric varieties. The results showed that natural mordants outperformed the chemical mordants. By doing so, this dyeing method suggested the possibility of using natural dyes with natural aids for viscose fabric coloring. Consequently, using extracted turmeric as a reliable dye source and a lemon as a bio-mordant could provide a beneficial insight for more environmentally friendly textile dyeing and manufacturing.