The aim of this work was to provide validity evidences of the short Spanish version of the Sexual Opinion Survey (SOS-6). First, a psychometric study was performed to examine the factorial invariance of the scale across different groups. A sample of 1,500 heterosexual adults (50% men, 50% women) from the general Spanish population, aged 18 to 80, was examined. Results showed that the unidimensional model of the SOS-6 is invariant across sex, age range, relationship status, and educational level. Secondly, a laboratory study was performed to determine the relationship between erotophilia and objective and subjective sexual arousal in response to sexual stimuli. The sample consisted of 130 young Spanish university students (46.92% men, 53.08% women) with heterosexual orientation. In men, erotophilia was related to subjective sexual arousal; in women, erotophilia was related to subjective sexual arousal and estimation of genital sensations. In conclusion, this work provides validity evidences of the short version of the SOS-6 and describes the factorial equivalence of the scale across groups and its concurrent validity.