Steam-assisted gravity drainage (SAGD) produced water (PW) consists of oil, solids, clays, petroleum-derived compounds, and other dissolved organic matters (DOMs), which make the SAGD PW highly stable and, therefore, very hard to treat. Developing a correlation between SAGD PW properties and dynamics of interfacial tension (IFT) between dispersed and continuous phases is important to understand the coalescence of dispersed phase droplets, which, in turn, leads to demulsifications of these difficult emulsions produced during SAGD operations. This work sheds light on the interfacial activity of SAGD PW endogenous surfactants, humic acids (HAs), as well as the interaction dynamics of these compounds with naphtha diluted Alberta oil sand bitumen (AOSB) present in a model SAGD PW. We quantify the dynamics of the IFT of a naphtha diluted AOSB oil drop in pure water as well as SAGD synthetic brine. Our results pinpoint the distinctive influence of the percentage weight composition of the naphtha-diluted AOSB and the surrounding model SAGD PW pH on the dynamics of this oil-water IFT. We anticipate that the results of this study will bring about a better understanding of interfacial film properties, leading to a predictable coalescence mechanism in SAGD PW emulsions, facilitating the design of next-generation SAGD deoiling unit operations.