The verb forms ending in -ra and -se in modern Spanish both correspond to the imperfect subjunctive, but their use is far from equal throughout the Spanish-speaking world. Rojo (1996) documents that the -se form is all but obsolete in the majority of American nations, and Kempas (2011) records rates of use in Spain ranging from 11% to 44%. The highest rate corresponds to usage patterns in Galicia, where contact with the regional language, Galician, may provide a conservative influence with respect to the shift from -se to -ra. The present study considers the effects of age, sex, and primary language, as well as linguistic factors such as possibility of the event (i.e., Lavandera (1975)) on the acceptability and choice of -se or -ra in the protasis of conditional statements in Galician Spanish. To accomplish this, 29 speakers completed an online acceptability rating task of 24 statements with varying combinations of verb forms in the protasis and apodosis. They were asked to correct those statements that they rejected as incorrect and unused in their own speech, and their produced corrections were compared to their acceptance or rejection of forms in the models. Results indicated that neither social factors nor possibility significantly affect the acceptance of phrases in -ra or -se. However, individual idiosyncrasies do affect the production of these verb forms, in line with results from Kempas (2011) and Rojo and Vázquez Rozas (2014).