Haircuts During the Three Weeks and Nine Days

Kvod HaRav,
Am I allowed to get a haircut during the Three Weeks.? Also, can my wife get a haircut before the Nine Days? Thank you

As is well known, it is a misswa to look presentable and well-groomed Likhvodh Shabath. This applies even during the week of Tish’a b’Av, as stated explicitly in the Mishna (Ta’aniyoth 4:6): שבת שחל תשעה באב להיות בתוכה – אסורים מלספר ומלכבס, ובחמישי מותרין מפני כבוד השבת.
The Mishna speaks of a case where 9 Av falls on a Friday, and states that on Erev 9 Av (Thursday) people may (and should) do whatever is necessary Likhvodh Shabath. Only one conclusion is possible: that K’vodh Shabath takes precedence over the mourning practices associated with this period. See Pisqe Riaz Ta’aniyoth 4:2:6.
The minhagh of not doing so for 3 weeks contradicts the Mishna, and should therefore be ignored. (Over the years I have asked many rabanim to explain how this minhagh might be justified. None could do so.) Therefore, if the length of your hair is such that you would normally go to the barber at this time, it is a misswa to do so.
The above applies to men. As for women who tend to cut their hair infrequently, they may get a haircut up until Rosh Hodhesh Av. If this did not work out, they should wait till after 9 Av.
It is worth pointing out that Hazal never spoke of mourning practices that apply for a period of three weeks. Hazal instructed us to refrain from certain types of activity from Rosh Hodhesh Av, and to begin observing mourning practices (e.g. haircuts) in earnest only the week of 9 Av. That these practices cannot impinge upon Kvodh Shabath was never in Question.
Rabbi David Bar-Hayim