Adjustable fittings for attaching support members to fluid conduits, including aircraft fuel conduits, are disclosed herein. An aircraft system in accordance with one embodiment of the invention includes a fluid conduit carried by an aircraft and a housing fixedly attached to the fluid conduit. The housing can include a first attachment feature having one of a projection extending outwardly from the housing or an aperture extending at least partially through the housing. The system further includes a support member having an attachment portion positioned proximate to the attachment feature. The attachment portion includes a support member aperture positioned over at least a portion of the first attachment feature. An adjustable fitting couples the support member to the housing. The adjustable fitting can include a first side, a second side opposite the first side, and an engagement portion at the second side positioned within at least a portion of the support member aperture. The fitting can also include a second attachment feature mated with the first attachment feature. The second attachment feature includes the other one of the projection or the aperture. The second attachment feature has a center point eccentrically offset from a center point of the fitting.