Self-tapping screws (STS) are widely used in timber connections due to their ease of installation and reliable mechanical performance. However, these connections can be significantly affected by moisture variations during construction and service life. Changes in moisture content (MC) in steel-to-wood connections may induce additional stresses, potentially compromising structural integrity. This study investigates the short-term performance of STS in steel-to-glulam connections, focusing on the effects of installation torque and moisture-induced dimensional changes in glulam. Experimental tests were conducted to quantify the axial load generated by torque and to assess the additional load resulting from swelling due to MC change. Varying levels of torque and moisture were applied independently to evaluate their individual impacts. The results show that combined torque and moisture exposure can induce axial load up to 82% of the screw’s factored tensile resistance. No screw failures were observed in any of the tested specimens under combined over torque and severe moisture exposure.