This study explored how social media is used as a destination marketing tool for the sustainability of heritage festival quality in Nigeria, drawing on the theory of planned behavior. The festival, which is an exploration of heritage, was specifically premeditated to celebrate the slave trade period by highlighting the unique connection of African American history to the diaspora ancestors who were literally taken away as slaves through “the point of no return” in Badagry, Nigeria. A structured questionnaire was utilized as a research instrument to gather information aimed at examining the influence of social media (SM), website quality (WQ), and online word of mouth (eWOM) on tourists’ festival satisfaction (FS) and festival revisiting intention (FRI). Data were gathered from samples of 473 diaspora tourists at Badagry Diaspora Festival in Nigeria and analyzed using partial least square structural equation modelling (PLS-SEM) with the aid of WarpPLS (7.0). The findings of the study revealed that social media (SM), festival quality (FQ), website quality (WQ), and electronic word of mouth (eWOM) had a positive and significant relationship with tourists’ festival satisfaction. Additionally, this study found that festival quality had a positive impact on the intention of the tourists to revisit the Badagry Diaspora Festival because tourist attitude is influenced by the socio-cultural background of tourists. Moreover, the result revealed the partial mediating effect of festival satisfaction in the relationship between (a) SM, (b) FQ, (c) WQ, and (d) eWOM and tourists’ festival satisfaction. Similarly, cultural motivation was also found to mediate the relationship between tourists’ festival satisfaction and festival revisiting intension (RI). Based on the findings, the implications of the festival sustainability and future research directions were discussed.