An adjustable transition duct support system for a transition duct that channels hot gases from a combustor exit to a gas turbine inlet of a turbine engine. The adjustable transition duct support system includes an adjustable forward transition flexible support assembly in contact with a transition duct body, whereby the forward transition flexible support assembly may be formed from a base extending toward the transition duct body and first and second side support arms extending from the base to the transition duct body. The first and second side support arms may be formed from a plurality of flex plates spaced from each other with spacers that provide rigidity in circumferential and radial directions and flexibility in an axial direction. The number of flex plates used may be varied to accommodate different turbine engines. The adjustable transition duct support system may have natural frequencies for circumferential and radial modes above two engine orders.