A topological Heyting algebra (THA) was defined by the author [Matematiche 32, 5-22 (1977; Zbl 0441.06010)] as a Heyting algebra endowed with a Kuratowski closure operator K and a Kuratowski interior operator I such that \(I(Kx\to Iy)=Kx\to Iy\) and \(K(Ix\to Ky)=Ix\to Ky\), where K and I are not supposed to be interdefinable. A bitopological space is a triple \({\mathcal X}=(X,K_ 1,K_ 2)\), where X is a set and \(K_ 1,K_ 2\) are Kuratowski closure operators on \({\mathcal P}(X)\) such that \(K_ 1K_ 2=K_ 1K_ 2K_ 1=K_ 2K_ 1K_ 2\). Let further \({\mathcal G}({\mathcal X})\) be the THA obtained by endowing the Heyting algebra \({\mathcal G}_ 1({\mathcal X})\) of all open subsets of \((X,K_ 1)\) with the operators \(K=K_ 2\upharpoonright {\mathcal G}_ 1({\mathcal X})\) and \(I=I_ 1I_ 2\upharpoonright {\mathcal G}_ 1({\mathcal X})\) where \(I_ h=\sim K_ h\sim\) \((h=1,2)\). Theorem. Every THA can be embedded into a THA of the form \({\mathcal G}({\mathcal X})\). This answers a question raised in a previous paper by the author [Riv. Mat. Univ. Parma, IV. Ser. 8, 91-106 (1982; Zbl 0519.06010)].