This article presents philological observations which may help to establish a relative chronology of some of theworks attributed to Śaṅkara. Commentaries on the Upaniṣads ascribed to Śaṅkara are compared to his commentaries on those parts of Brahma-Sūtras that discuss the same Upaniṣadic passages. Closer investigation of some of these passages might lead to some conclusions about the chronology of these works. The article investigates examples from Taittirīya-Upaniṣad 2.1–5 and Bṛhadāraṇyaka-Upaniṣad 3.7 respectively discussed in Brahmasūtra-Bhāṣya 1.1.12–1.1.19 and 1.2.18–20, an example from Kaṭha-Upaniṣad 1.3.1 (3.1), which is presented both in Brahmasūtra-Bhāṣya 1.2.11–12 and in Kaṭhopaniṣad-Bhāṣya 1.3.1, together with some examples of interpretations of the same verses in different Upaniṣads, such as the verse which occurs as Muṇḍaka-Upaniṣad 2.2.10 and Kaṭha-Upaniṣad 2.2.15 (5.15) and two verses shared by Īśā-Upaniṣad, Kaṭha-Upaniṣad and Bṛhadāraṇyaka-Upaniṣad. These examples will reveal some textual parallels in these commentaries, which might provide some clues for establishing a chronology of these passages.