A novel sensor for simultaneous temperature and strain measurement based on fiber interference is proposed. The sensor is formed by incorporating a long-period fiber grating (LPFG) inside a Lyot fiber filter (LFF), in which the LFF can be constructed by placing a polarization maintaining fiber (PMF) between two polarizers (PL) with the primary axis of the fiber rotated 45° relative to the polarizer axes. Due to the different responses of the LFF and LPFG to temperature and strain variations, it is possible for the proposed fiber sensor to measure temperature and strain simultaneously by use of a well-conditioned sensitivity matrix equation. The experimental temperature sensitivity coefficients of LFF and LPFG are -1.3173 nm/℃ and 0.0604 nm/℃, respectively. The strain sensitivity coefficients achieve -0.0185 nm/με and -0.0004 nm/με, respectively. A sensing resolution of ±1 ℃ in temperature and ±25 με in strain has been experimentally obtained. The experimental results are in good agreement with the theoretical analysis. Furthermore, this linear configuration is simple and easy to achieve, and has high stability and sensitivity.