PurposeThe aim of this paper is double: firstly, to examine the presence of herd behavior in four MENA stock markets (the Egyptian, Jordanian, Moroccan and Tunisian markets), and secondly, to study the anchoring behavior in these markets.Design/methodology/approachThe authors employ quantile regression analysis for testing herding bias in the MENA region, following the methodology of Chiang and Zheng (2010). Regarding the evaluation of anchoring bias, the authors follow the methodology of Lee et al. (2020). The study uses daily stock index returns ranging from April 1, 2011, to July 31, 2019, as well as CAC40 and NASDAQ returns.FindingsThe authors find evidence of herding during down-market periods in the lower tail for Egypt, Jordan and Tunisia, while this bias is detected during up-market periods in the lower tail for Morocco. In addition, based on historical returns, the authors conclude that there is a momentum effect in these markets, and they are dependent on the CAC40 and NASDAQ indices.Practical implicationsThis paper confirms the findings of previous works devoted to some emerging markets such as China, Japan and Hong Kong, where anchoring and herding are considered the most important and impactful heuristic and cognitive biases in making decisions under uncertainty, particularly during down-market periods.Originality/valueThe paper contributes to the empirical literature in herding and anchoring biases for MENA countries. The absence of empirical work on the effect of these biases on stock prices in emerging markets and those of the MENA zone leads to the discussion of the impact of psychological biases on these of markets.