Tefillin III: In Practice תפילין (ג): למעשה

Tashbetz Katan (Student of Maharam, in his name), 21

One should not protest their [women’s] wrapping themselves in tzitzit and reciting a beracha on it because they can obligate themselves, as is proven in Kiddushin (31). But they should not lay tefillin because they do not know how to keep themselves in purity.

Rav Yechi'el Ya'akov Weinberg, Responsa Seridei Eish II:41

“Michal bat Shaul laid tefillin and the sages did not protest it.” This is difficult. Why didn’t they protest it? Is she not prohibited from wearing tefillin because of “a man’s article shall not be on a woman”? It must be that, since her intention is for the sake of the mitzva, there is no prohibition here of not wearing [a man’s garb].

Maharam Schick OC 15

It is yuhara…and there is a concern that also others will follow her example [Michal bat Sha’ul] although they are not scrupulous [with regard to matters of piety].

Yalkut Yosef, Tzitzit U-tfillin 37:5

…In general it is not fitting to lay tefillin shel shimusha rabba at mincha publicly, in a place where no member of the community lays tefillin at mincha, for one should be concerned for yuhara. But a person who is known for his true piety is permitted to lay tefillin shel shimusha rabba at mincha, even in a place where the community do not lay tefillin at mincha. Anyone who lays them in private need not be concerned for yuhara.

Hagahot Maimoniyot (Student of Maharam), Laws of Tzitzit 3:40

I again found in the name of a great [scholar] that wherever there is a concern of a hint of transgression as in…laying tefillin because of uncovering erva [nakedness], since ‘a woman’s hair is [tantamount to] nakedness’…in all these types of cases we protest them [women].

Shiltei Gibborim Rosh Ha-Shana 9b

So too it is prohibited for women to lay tefillin, even without a beracha, for it appears like ‘the way of the separatists’ (Mishna Megilla 4:8) who transgress the words of the sages and do not wish to expound the verses according them.

Rabbanit Malka Puterkovsky, “The Halacha of Women and Laying Tefillin,” Mehalechet Be-darkah, p. 151

Although in the era of the ”rishonim” there were many halachic authorities who permitted women to fulfill the mitzva of tefillin…if a consensus formed in the era of the acharonim [later authorities] that it is not fitting for a woman to lay tefillin, [then] because of the binding halachic principle that “halacha is in accordance with the later authorities,” one must accept this decision straightforwardly in halachic practice, unless there are qualitative rationales with the power to change it in our time

Rav Herschel Schachter, 'The Entire Assembly is Holy'

What is the rationale of those who permit? …as everyone knows, thus was the received practice from past generations, and who is he that gives the go ahead and is brazen to rule against a received ruling of our Rabbi the Rema……And the expression used by some who permit “that according to halacha” a certain action is permissible, and that those who are stringent want to forbid it only for “political reasons,” is incorrect. For this matter of changing tradition also constitutes an integral part of halacha…

Iggerot Moshe, OC 4:49

Indeed, every woman is permitted to fulfill even mitzvot in which the Torah did not obligate them, and they have performed a mitzva and receive reward when fulfilling these mitzvot…Only regarding laying tefillin did Tosafot write that one needs to protest them because tefillin require extra zealousness with a guf naki and hese’ach ha-da’at, for which reason even men – who are obligated in tefillin – refrain from laying them all day long, rather just the brief time of the shacharit prayer, and so ruled Rema…

Rav Ya'akov Ariel, Authentic Femininity vs. Imitation

If a woman feels a deep need in her soul to fulfill these mitzvot [tzitzit and tefillin], she has, perhaps, on whom to rely.