The present research scrutinized the use of politeness strategies in gratitude expressions of English and Persian users of Instagram. For that purpose, 200 gratitude posts were collected, 100 of which belonged to English users and the other 100 posts were composed by Persian users of Instagram. This investigation alsoevaluated gender roles in the production of gratitude utterances. Seeking to discover the politeness patterns for each language on Instagram, the data were analyzed based on Brown and Levinson's (1987) taxonomy of positive and negative politeness strategies. The findings suggested some differences in the use of the second (Exaggeration), the forth (Use of in-group identity markers), and seventh (Presuppose/raise/assert common ground) positive politeness strategies, and the seventh negative politeness strategy (Impersonalizing the speaker and the hearer) between the English and Persian users which might be due to some existent cultural transfer, and regarding the gender investigation, no significant differences were observed between females and males of each language. This is indicative of the idea that Instagram has turned into a distinguished genre of language possessing certain features such as gender-free, direct, and intimate language.