Does one wear Tefillin on Chol ha-Moed Pesach?
Many refrain from wearing Tefillin on Chol ha-Moed. Some wear Tefillin but refrain from reciting a berachah.
You should follow the practice of your local community, and where there is no set practice, your family custom.
Some Rishonim write that one does not wear Tefillin on Chol ha-Moed. These include the Behag (cited by Tosafos, Moed Kattan 19a), the Rambam (Yom Tov 7:13) and the Rashba (1:690).
Others, however, write that Tefillin are worn on Chol ha-Moed, including many Ashkenazi authorities such as the Rosh (Tefillin 16), the Or Zarua and Maharam.
As a compromise, the Tur (Orach Chaim 31) cites a number of authorities who advise that Tefillin should be worn, but the berachah omitted.
In practice, the Shulchan Aruch (31:2) rules that it is Sephardi custom to refrain altogether from wearing Tefillin on Chol ha-Moed, for reasons rooted in Kaballah. This is the universal Sephardi custom, and Chassidim likewise refrain from wearing Tefillin on Chol ha-Moed.
The Rema adds that the Ashkenaz custom is to wear Tefillin and recite a berachah, but because of the sensitivity of the topic the berachah should be recited quietly. Later authorities espouse the compromise noted by the Tur, meaning that Tefillin are worn but the berachah is not recited (see Taz 31:2; Mishnah Berurah 31:8).
Moreover, the custom among Ashkenazim in Israel is to follow the ruling of the Vilna Gaon, who ruled that one should refrain altogether from wearing Tefillin. It is recorded that this was also the custom in Volozhin.