This paper is devoted to the relationship between almost limited operators and weakly compact operators. We show that ifFis aσ-Dedekind complete Banach lattice, then every almost limited operatorT:E→Fis weakly compact if and only ifEis reflexive or the norm ofFis order continuous. Also, we show that ifEis aσ-Dedekind complete Banach lattice, then the square of every positive almost limited operatorT:E→Eis weakly compact if and only if the norm ofEis order continuous.