Herein, two refractive index sensors based on exposed-core side-hole fiber Bragg gratings (SH-FBGs) with D-shaped and X-shaped fiber cross sections were proposed and demonstrated. One SH-FBG sensor with the D-shaped fiber cross section was fabricated using the side-polishing technique, in which an air hole of the side-hole fiber (SHF) engraved with the FBG is polished. Another SH-FBG sensor with the X-shaped fiber cross section was developed using the wet chemical etching method, in which two air holes of the SHF engraved with the FBG are etched. The refractive index sensitivities of the first and second sensors are measured to be 24.0 and 15.1 nm/RIU (RIU is the unit refractive index), respectively, for the refractive index of approximately 1.380 and 1.333?1.340, respectively. The 15.1 nm/RIU value can be further optimized using the corrosion scheme. Because the X-shaped SH-FBG sensor shows two polarized reflection peaks owing to birefringence and exhibits different responses to changes in external refractive index yet the same response to temperature variations, it can be used as a temperature-independent refractive index sensor. The air holes of the designed two sensors can be used as microfluidic channels, potentially simultaneously facilitating online detection and drug delivery. Our device is characterized by structural simplification and easy operation and thus is potentially useful for biosensing and medical applications.