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The easy way to sew a triangle crotch leggings gusset: Aila tutorial

The Aila leggings has an optional triangle crotch gusset. Now sewing gussets can feel a little bit overwhelming if you are not used to sewing these type of garments. But don’t worry, this simple 3-step method makes attaching a triangle gusset a breeze!

1. Attach one side of gusset to the crotch

Sew the gusset from the base of the triangle to the tip using a stretch stitch or a narrow zigzag stitch. Stop sewing when you hit the tip of the triangle. This will be easier if the gusset layer is on top when you are sewing.

Learn more: Best Fabric Choices for Workout Leggings: Aila Sew-Along

Tip: To prevent the edges of the gusset from slipping, use a dab of basting glue or just use a regular glue stick. You can also baste the entire side before you use the stretch stitch (image below)

2. Sew the entire back crotch seam

With this method, you’ll sew the crotch seam and the other side (leg) of the triangle gusset in one continuous seam. Place the back crotch pieces together and start from the base of the triangle and sew to the waist. Make sure the opposite seam allowance on the gusset is folded outwards.

Learn more: Video: Sew Your Best Leggings Ever

3. Topstitch the gusset

To avoid chafing seams, you can topstitch the gusset seams using some type of decorative sewing machine stitch that has a good stretch. I recommend doing a sample first to make sure the seam will both work and look good.

You can either stitch over the folded seam allowance.

Another option is to sew the crotch seams using a zigzag stitch and then press the seam allowance apart. This will make topstitching easier since the seam is much less bulky. In this example, I’m using the 3-needle coverstitch to crate a mock-flatlock effect. But you can also use a decorative sewing machine stitch.

Learn more: How to Hem Leggings: Aila Sew-Along

A third option is to just use the 2- or 3-thread flatlock serger seam and sew the entire crotch area using that stitch. A serger flatlock is however less durable than the method described above, but it can look very similar to a professional flatlock stitch and there will be no chafing seams on the inside.

Stitch together the remaining seams

Start by sewing the front crotch seam. Then sew the entire inseams. Start from the lower leg opening and sew the entire leg seam including the gusset in one continuous seam from leg opening to leg opening. Make sure the gusset’s seams are folded outwards, and that the front crotch seam aligns with the triangle midpoint

The finished gusset

That’s it! I know some other pattern companies use a more intricate notch system for their triangle gussets, and that is helpful too, but this method really simplifies the process even more and works just as well in my humble opinion.

Using a crotch gusset is an option that comes down to preference, hence why I made it optional for my Aila leggings sewing pattern. But it does help increase the lateral range of movement and can prevent chafing too, so worth giving it a try for sure!

Watch this video tutorial for even more sewing leggings tips!


  • Dawn
    May 21, 2016 at 2:24 pm

    I think your directions are exactly the same as the Jalie directions, aren't they? Or maybe I missed something.

    • Johanna
      May 21, 2016 at 2:59 pm

      The difference is that they don't sew the gusset from end to end, they just between the notches on the gusset and then fold it to align with the seam allowance of the other pattern pieces (I think?) That is the part that confuses me!

  • paloverdeblooms
    May 21, 2016 at 7:27 pm

    I've never done a triangular gusset, only diamond-shaped ones under the arms. But that said, I don't think I've ever followed anyone's directions. I just look at the what needs to be inserted and put it in. I don't see it as being particularly difficult. Your method for the crotch gusset looks quite efficient to me.

    • Johanna
      May 23, 2016 at 9:20 am

      That is what I'm prone to do too. But then I struggle with the feeling that I'm not doing it the "right" way. But maybe there is no one right way 🙂

  • Summer Flies
    May 22, 2016 at 12:03 am

    I haven't done a triangle gusset yet but have some leggings planned so this is very helpful. I haven't got Jalie leggings (just some swimwear patterns) but although they get a lot of kudos for their instructions, I have found some confusing and some missing. Maybe if you have done it before it makes more sense but overall they are ok but I wouldn't say they are the best.

    • Johanna
      May 23, 2016 at 9:21 am

      I agree about Jalie. Some steps are brilliantly explained, though others not so much or use a method that is quite fussy.

  • Kyle
    May 22, 2016 at 4:15 pm

    I don't think I've ever inserted a crotch gusset but your method is what I will use when I get to that point!

    • Johanna
      May 23, 2016 at 9:22 am

      Yes please do, and get back to me with any feedback!

      • Lucie ladouceur
        March 1, 2018 at 3:04 pm

        Could you put light material on dark so we can see better -i always have so much trouble with this. thanks lucie

        • Johanna
          March 1, 2018 at 3:19 pm

          Hi! Totally agree it would make it easier, but since I do many tutorials when I’m working on an actual project (saving time and all that) I’m not always able to use a contrasting thread. But yes it would make it easier to see visually for sure!

  • Ann
    May 22, 2016 at 7:59 pm

    I really appreciate this! I agonized over a gusset recently and my aunt had to help me. I'm still scared of doing another one without her around.

    • Johanna
      May 23, 2016 at 9:23 am

      Gussets are hard, especially the diamond version. I think there is something about the construction that is so different from other sewing steps that it is easy to get confused

  • LinB
    May 23, 2016 at 6:01 pm

    Have you ever tried ovoid gussets? V. useful to add room along a seam in a ready-to-wear garment that is too tight somewhere. I like a long, thin ovoid that is fattest wear most needed, with long legs that are easy to ease into the length of a seam. Easier than sharp points to insert, anyway.

  • […] Johanna from Last Stitch blog also has a great tutorial on how to insert a triangle crotch gusset which is slightly easier than a whole diamond or almond shaped gusset. I have been noticing this gusset RTW clothes more often lately. Read the post HERE. […]

  • Rebecka Lindberg
    April 4, 2018 at 8:54 am

    What is the purpose/function of the gusset? It adds some space and mobility?

  • Mary
    October 4, 2019 at 6:43 pm

    I have difficulty inserting a gusset neatly. Your seams look as if they are done on a much newer machine than my old Bernina. The best I can do is a zigzag stitch or perhaps just a straight topstitch would be okay.

    I should be grateful for any comments/ideas

  • […] My own leggings sewing pattern that comes with an optional triangle gusset so that you have both options at hand. Includes two different pocket options as well, since I know how valuable a pocket can be on a pair of leggings. I’ve also down a tutorial on the easiest way to sew a triangle gusset. […]

  • Erica
    April 23, 2021 at 3:44 am

    Those leggings you are holding in the video are amazing! Fantastic fabric!
    I love your tip regarding using mesh lining in the waistband and will be using that idea as I finish my first pair of leggings tomorrow. Had I found your website before now, I would have looked into your legging pattern to make them but will be checking into it for future leggings.

  • […] there is! I already have a very detailed illustrated step-by-step tutorial on sewing the gusset of Aila […]

  • […] Learn more: Easy Way to Sew a Triangle Crotch Leggings Gusset […]

  • […] than blindly grabbing any leggings, choose the variant with a gusset in the middle. It’s the area where all the stitching combines while bridging the gap between the leg […]

  • Valeria
    July 10, 2023 at 8:07 pm

    Could you please explain what’s the decorative stitch you used as a cover stitch on grey leggings? Was it done on regular sewing machine? It lies so nice and flat! When I try using zigzag as a ”cover stitch” over an overlocked seam it gets wavy and stiff. Tried different decorative stitches as well, they look okay when I do sample on a fabric, but pucker when I do it over the overlocked seam. Any suggestions how to prevent this?


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