About

Big Sky Therapeutic Services, PLLC, is an independent mental and behavioral health treatment center that was formed in 2006 by Brett Gilleo, LCPC, LMFT, and BCBA, located in Great Falls, MT. Since then, we have grown to include 15 staff members. We hold a combined total of more than 70 years experience to serve all clients’ needs and ensure high-quality results.

Originally, our services included only outpatient mental health services. Since starting Big Sky Therapeutic Services, we expanded services to include in-home parenting, in-home early intervention services, ABA (Applied Behavioral Analysis), behavioral health services, consultation, and other related services.

Our current goal is to grow as a company by increasing services for individuals with autism, related disorders, and other behavioral health disorders to help families and agencies meet the needs of our population. For more information about our services, click on the “Services” tab and click on a service type.


Our staff

Brett E. Gilleo, LCPC, LMFT, BCBA

Brett E. Gilleo, LCPC, LMFT, BCBA

LCPC: Licensed Clinical Professional Counselor
LMFT: Licensed Marriage and Family Therapist
BCBA: Board Certified Behavior Analyst

Brett has been working in the mental health field for many years. I earned a bachelor’s degree in Counseling Psychology from the University of Great Falls, now University of Providence, in 1997, obtained a Master of Science degree in counseling in 2000, and became a Licensed Clinical Professional Counselor (LCPC) in 2001.

In 2012, I obtained a second master’s degree in special education from Montana State University in Billings and achieved status as a Board-Certified Behavior Analyst (BCBA) in 2014. The BCBA certification furthered my work in the field of autism spectrum disorders, as well as severe disruptive behavioral health disorders.

During my career, I have worked for Full Circle Counseling Solutions, A.W.A.R.E., Inc., and Center for Mental Health. I currently own and operate Big Sky Therapeutic Services, PLLC, which I started in 2006.

I consult with schools, daycares, Head Start programs, agencies, and families across Montana to help assess and design intensive behavioral health intervention plans for youth with various challenges. My community service includes volunteering my time to serve on the board for the Very Special Arts (VSA) program in Montana (2007-2016), Great Falls Early Childhood Coalition (GFECC) from 2011-2020, Friends of Autism Great Falls (2015-present), and Sensibility: Autism School from 2017- 2019 as well as Boy Scouts of America.

I spend much of my time providing training, support, and mental health counseling for the autism spectrum population, as well as assisting families in advocating for special education services for their children. Although the field can be challenging, I genuinely love my work and find helping others highly rewarding.


Nicole, BCBA: Board Certified Behavior Analyst

Nicole

BCBA: Board Certified Behavior Analyst

Nicole began working in the field of ABA as a registered behavior technician in 2019. I became a Board-Certified Behavior Analyst (BCBA) in 2020.

Prior to working in the ABA field, I was a special education teacher both in residential treatment facilities and public schools. I stumbled upon ABA while trying to find a way to support my students that couldn’t access education due to challenging and dangerous behaviors. I find it rewarding to teach kids the foundational skills they need in order to learn and access education.

I have experience working with individuals of all ages in their homes, in clinics, in residential placements, and in school-based settings. I have a bachelor’s degree in Elementary Education and Special Education from Montana State University. In 2020 I received my Master’s degree in Educational Psychology from the University of Southern Maine.

I enjoy reading, playing games, and going on walks and bike rides with my husband, son, and dog.


Tess, BCBA: Board Certified Behavior Analyst

Tess

BCBA: Board Certified Behavior Analyst

Tess is originally from Hungry Horse, Montana. I completed my undergraduate degree at Montana State University in 2010 and completed my Masters in Applied Behavior Analysis at The Chicago School of Professional Psychology in 2013.

I am very passionate about providing meaningful changes to allow families the freedom to access the community without fear of how their child/children will react to the situation.  I am also passionate about providing supports for parents/caregivers to manage challenging moments.  I provided ABA Therapy to families in Seattle, Washington for 8 years and in Livingston Montana for 2 years before coming to Great Falls and joining Big Sky Therapeutic Services.

In my free time I can be found playing with my two boys.   I love going for walks with them and my husband.  I also love crafting and will crochet or knit items for my family.  I enjoy reading/listening to audio books as well as playing/listening to music.


Alicia, RBT: Registered Behavioral Technician

Alicia

Lead RBT: Registered Behavior Technician

Alicia began working as a Direct Support Professional with adults with intellectual disabilities in 2019 and I have worked in a variety of areas in the medical field over the years. My interest in the field of ABA Therapy started when I saw how beneficial ABA Therapy was for a close family member. Wanting to be a part of that work I became a registered behavioral technician in February of 2024. I put my heart into the care of each client and enjoy watching them grow and develop.

In my free time, I enjoy spending time with my family and dogs. I enjoy going on adventures and being outdoors when the Montana weather allows.


Azaya,  RBT: Registered Behavior Technician

Azaya

RBT: Registered Behavior Technician

Azaya has been working with individuals with developmental disabilities for many years. My love for this population lead me to obtain my certification as a Registered Behavioral Technician (RBT). I have an Associates of Arts degree and am currently continuing my education in ABA services to become a BCBA.

I began working with developmentally disabled elderly adults originally from state facilities in a group home setting. Because of this, I am very passionate about clients’ rights, dignity, choice and living a fulfilling life. This is where I began learning about ABA services and the benefits of early intervention for those on the autism spectrum. I then switched to working with kids, in home and center while I was still living in Arizona. Once moving to Montana, I knew I wanted to continue on this path and find a clinic with the same ideals as I had. Big Sky Therapeutic Services was the place for me to continue growing and learning in the ABA environment. Here I can share my past knowledge and experience with our children and families.

When not working you can find me spending time with my family and dogs, going on adventures to new places, learning new things or taking photos of all the beautiful places I go.


Ben, RBT: Registered Behavior Technician

Ben

RBT: Registered Behavior Technician

Ben grew up in Virginia, graduating in 2019 from Hampden-Sydney College with a bachelor’s degree in psychology. From 2019 to 2024, I enjoyed teaching Taekwondo in my hometown. After moving to Montana in the Summer of 2024, I began my journey into the behavioral health field. I joined Big Sky Therapy in August of 2024. I am passionate about helping others and enjoy seeing the people I help grow and develop.

In my free time, I enjoy exploring the outdoors, playing video games, and spending time with friends and family.


Kye, RBT: Registered Behavior Technician

Kye

RBT: Registered Behavioral Technician

Kye, was born and raised in Great Falls. I have worked with children who ranged in the ages of 5 through 11 providing assistance with homework, playing, and doing lesson plans prior to working at Big Sky Therapy. I have also enjoyed working with dogs, providing all of their basic needs. I began working at Big Sky Therapeutic Services as a Registered Behavioral Technician in 2024. I have a passion for helping people. I enjoy working with the children watching them develop, grow, and celebrate their achievements. I learn as much from the children as they do from me, which I find very rewarding.

When not at work, I enjoy various activities, such as collecting vintage items, puzzles, playing video games, board games, and even enjoying a good game of bingo. Additionally, I enjoy spending time with my family and friends and building new connections.


Riley, RBT: Registered Behavior Technician

Riley

RBT: Registered Behavior Technician

Riley has worked with children in various settings for many years. I intend to dedicate my life and career to working with children with special needs. I have enjoyed volunteering with Camp Francis Children’s Bereavement Program through Peace Hospice since 2018. I have also worked at Malmstrom AFB’s Youth Programs and continue to serve as a volunteer for Malmstrom’s Exceptional Family Member Program. I received my bachelor’s degree from Washington State University in 2024, majoring in Psychology with a minor in Human Development. I was born and raised in Great Falls and am very happy to be back serving my hometown community. I joined the Big Sky Therapeutic team in 2025 to continue sharing my passion for working with children and making a positive impact in their lives.

When I am not at work, you can find me spending time with my cat and bunny, crocheting and watching movies, or camping, hiking, and kayaking with my family.


Cherie,  Office Manager

Cherie

Office Manager

Cherie joined BSTS in 2019 as the Office Manager. I enjoy helping the staff, clients, and their families to make sure everyone has what they need. I graduated with a bachelor’s degree in Business Management from Northern Arizona University and have a long career of managing businesses as well as working with special needs children and their families. My volunteer and paid positions have given me a true passion for this special population. I sat on the board for Friends of Autism, Youth Employment Task Force as well as the planning committee for MY Transition Conference where I was a keynote speaker with my son in 2021. My experience and knowledge help keep Big Sky Therapeutic Services running smoothly. I love talking with families and celebrating their wins.

Outside of work I enjoy spending time with her family, playing with her grandchild, traveling and learning together.


Cyndi, Administrative Assistant

Cyndi

Administrative Assistant

Cyndi started with BSTS in 2025. I have a background working with medical insurance companies to obtain accurate payment and appropriate authorizations, as well as accounting. I retired once but learned I like working part time. I am detail oriented and enjoy working on projects. I was not born in Montana but “got here as quick as I could” moving here years ago with my husband. We fell in love with Great Falls and don’t plan to ever leave the area. Outside of work I am active in my church and enjoy teaching Sunday School to our youth. I also love gardening and my dog, Bella Joy.