This thesis investigated possible effects of explicit and implicit focus on form (FonF) instruction on the acquisition of Spanish future of probability (SFP) by Anglophone and Francophone students at a Canadian bilingual university. We also analyzed a possible L1 transfer from French to L2 Spanish in the acquisition of SFP, due to the typological similarity of this linguistic feature in the two languages. Twenty seven B1/B2 Spanish level students including L1 English and L1 French learners of L2 Spanish were divided into three groups according to the instruction type: explicit focus on form instruction group, implicit focus on form instruction group and control group, which received no additional instruction. All the participants were tested before the lesson (pretest), immediately after (posttest) and four weeks later (delayed posttest). The battery of tests included Untimed Grammaticality Judgment (UGJT), Written Production (WPT) and Oral Production (OPT) tasks. They aimed to test our four hypotheses which focused on both short-term and long-term effects of the two types of instruction on grammaticality judgment, written and oral production of SFP, respectively. The results demonstrated a positive effect of explicit and implicit FonF instruction on grammaticality judgment, oral and written production of SFP compared to the control group. In particular, both instructional groups distinguished grammatical and ungrammatical uses of SFP with state and activity verbs immediately after the treatment. After four weeks, both groups retained the acquired knowledge equally well. In the implicit FonF group we found an advantage of the L1 French over the L1 English students, possibly due to the similarity of the future tense morphology in Spanish and French, as well as the fact that French uses future morphology for present time probability, although in very limited contexts (a subset of state verbs). The results of the WPT suggest an advantage of the explicit FonF group in both immediate and long-term results and showed no difference between the L1s in either of the instructional groups. We also noticed an overgeneralization of the use of SFP with telic verbs in both instructional groups after the treatment, which is considered ungrammatical. Therefore, our participants did not distinguish the written use of telic and atelic verbs in epistemic conditions after the two types of treatment provided. The OPT results demonstrated that similarly to the previous two tasks both experimental groups performed better than the Control group. However, there was no significant difference between the two instructional groups. L1 had no significant effect on the oral production of SFP either. Similarly to the WPT, we found an overgeneralization of the use of SFP in telic verb conditions. Overall, Anglophone and Francophone students appear to have similar opportunities for successful acquisition of SFP and both explicit and implicit FonF instruction, activities and feedback may lead to positive results in the acquisition of SFP. To conclude this thesis, we discuss some challenges of this study and possible directions of future research.