Locked Classroom Doors: What the Research Says and How Schools Can Improve Staff Buy-In

Keeping classroom doors closed and locked is widely recognized as an important school security practice. But implementing that practice consistently throughout a school building or district can be more complicated than writing it into a policy.

That challenge recently surfaced in the National Council of School Safety Directors (NCSSD) community when a member asked colleagues how they had gained staff buy-in for requiring classroom doors to remain closed and locked throughout the school day. The district had already shared research, best practices and firsthand experiences, and its unions supported the initiative. Still, school safety leaders were encountering resistance.

The question generated responses from other NCSSD members who had faced many of the same challenges. Their experiences reflect a larger lesson found repeatedly in school shooting investigations and emerging research: A classroom door can only provide protection if it functions properly and is actually secured.

A 2026 study from Texas State University's Advanced Law Enforcement Rapid Response Training (ALERRT) Center examined 54 K-12 active shooter incidents between 2000 and 2025. Researchers found that unsecured doors were a recurring point of vulnerability, while no functioning locked door examined in the study was successfully breached by defeating its locking mechanism.

Those findings add new data to lessons documented after some of the nation's most significant school shootings, including Sandy Hook, Parkland, and Uvalde. More recently, survivor accounts from the 2024 shooting at Apalachee High School illustrated in stark terms how a locked classroom door can influence an attacker's movement.

So what does it take to translate those lessons into everyday practice?

For NCSSD members who have implemented closed-and-locked classroom policies, the answer involves more than simply telling teachers to lock their doors. It requires the right hardware, workable procedures, training, leadership support and, in some cases, accountability.

The Role of Locked Classroom Doors in Past School Shootings

The findings from ALERRT reinforce lessons that have emerged from investigations into school shootings for more than a decade.

Following the 2012 shooting at Sandy Hook Elementary School, the Sandy Hook Advisory Commission recommended that all K-12 classrooms be equipped with doors that can be locked from the inside by a teacher or substitute teacher.

“The Commission cannot emphasize enough the importance of this recommendation,” the commission wrote in its final report. “The testimony and other evidence presented to the Commission reveals that there has never been an event in which an active shooter breached a locked classroom door.”

The commission did not suggest a specific type of lock, but emphasized that classroom doors should be lockable from inside the room. It also recognized that school security measures must account for the educational environment, recommending approaches that enhance rather than diminish the educational experience.

Parkland: Classroom Door and Access Control Failures

Following the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, the state commission investigating the attack identified several failures involving doors and access control.

The shooter entered the school's Building 12 through an unlocked and unstaffed exterior door, which the commission characterized as a security failure. Investigators also found that classroom doors in the building could only be locked from the exterior and that teachers did not consistently keep them locked. Some classroom doors were unlocked when the shooting began.

The commission noted that teachers were reluctant to enter the hallway during the attack to lock their doors, highlighting the importance of having classroom doors that can be secured from inside without exposing staff to the threat.

Uvalde: Classroom Door and Lock Failures

The 2022 shooting at Robb Elementary School in Uvalde, Texas, illustrated another challenge: A district can have door security policies in place, but those policies provide little protection when they are not consistently followed or the hardware does not function as intended.

The Texas House investigative committee found that the exterior door the shooter used to enter the school was supposed to remain locked but was unlocked when he approached. Investigators concluded that a locked door likely would have slowed the attacker as he attempted to overcome it or find another way into the building.

Problems extended to classroom doors. Teachers commonly left interior doors unlocked, and magnets or other methods were sometimes used to circumvent the locks. The door to Room 111, where the attacker entered, also had a history of problems. Its teacher had previously reported that the door did not always lock, and investigators found no corresponding maintenance work order.

The committee concluded that the door to Room 111 was likely unlocked during the attack and that the shooter did not have to overcome a locked classroom door to enter.

“Locking the exterior and interior doors ultimately may not have been enough to stop the attacker from entering the building and classrooms,” the committee wrote. “But had school personnel locked the doors as the school's policy required, that could have slowed his progress for a few precious minutes—long enough to receive alerts, hide children, and lock doors.”

Apalachee: How a Locked Classroom Door Changed the Shooter’s Path

The 2024 shooting at Apalachee High School in Georgia provides a more recent example of what can happen when a classroom is already secured before a threat is recognized.

According to survivor accounts, the shooter left his algebra classroom before the attack. Because the classroom door locked automatically, he could not just walk back in when he returned.

A student went to let him inside but saw that he had a gun and refused to open the door. Unable to re-enter the classroom, the shooter moved on and opened fire nearby.

The account was shared in the NCSSD discussion as a resource for helping staff understand the importance of keeping classroom doors secured throughout the school day. It also illustrates an important distinction for school leaders considering their own procedures: A classroom door that can be locked during an emergency is not the same as a classroom door that is already locked when an emergency begins.

In an active threat situation, occupants may have little or no warning before an attacker reaches their classroom. Keeping a functioning door secured eliminates the additional step of recognizing the threat and locking the door after an emergency is already underway.

Challenges With Keeping Classroom Doors Closed and Locked

Despite the evidence supporting locked classroom doors, implementing a closed-and-locked policy can create practical challenges during the school day. This was particularly evident in the recent NCSSD discussion, where several members said they had encountered the greatest resistance at the elementary level.

One recurring concern was the disruption caused when students leave the classroom for the restroom, services or other activities and must be let back into a locked room. In elementary schools, even something as simple as knocking can present a challenge for younger students.

One NCSSD member said their district responded to that concern by providing small doorbells for classrooms after staff pointed out that younger students sometimes could not knock loudly enough to be heard. The district wasn't able to eliminate every interruption associated with the policy, but after several years, the member said keeping classroom doors secured had largely become part of the routine.

Other members cautioned that districts should consider how their procedures affect instruction and student movement rather than assuming compliance will follow simply because a policy has been adopted.

One school safety professional recommended involving teachers directly in developing procedures that minimize instructional disruptions while maintaining a closed and locked classroom door. That could include reducing unnecessary student movement during instructional periods and establishing clear re-entry or hall pass procedures.

The member also raised another important consideration: Students should not routinely be placed in the position of making security decisions about who is allowed through a secured classroom door.

These operational concerns don't necessarily change the security objective, but NCSSD members suggested that addressing them can make the difference between a policy that exists on paper and one that is consistently followed in practice.

How NCSSD Members Are Addressing Staff Buy-In and Compliance

For NCSSD members who have faced resistance to closed-and-locked classroom policies, providing research or explaining the rationale hasn't always been enough. Members described several strategies that helped staff better understand the importance of the practice and made implementation more manageable.

Use Demonstrations to Show Why Locked Doors Matter

Several members said hands-on demonstrations were among the most effective ways to change perceptions.

One member recommended incorporating the issue into a progressive drill or functional exercise that allows staff to see how an unsecured classroom changes their options during an emergency.

Another member described conducting the same intruder scenario twice for staff. In the first, the classroom door was open. In the second, the door was already closed and locked.

"It was very eye-opening for some of the naysayers," the member said.

For districts that aren't prepared to conduct that type of exercise, another NCSSD member recommended using survivor accounts to demonstrate why the everyday condition of a classroom door matters, pointing specifically to the Apalachee High School interview discussed earlier.

Whether through exercises or real-world examples, members said demonstrating the potential consequences can help staff understand why classrooms should already be secured before an emergency begins.

Use Door Hardware That Supports Everyday Compliance

Members also emphasized addressing the everyday obstacles that can lead staff to circumvent a security procedure.

Some districts have installed hardware that allows classroom doors to remain locked at all times, eliminating the need for teachers to remember to lock them during an emergency. One member described a district policy that requires doors to remain in the locked position but does not require them to remain closed. If an emergency occurs, teachers can simply close the door and it is immediately secured. Another member described doors that automatically lock when they close, while another said their district had recently replaced locks so they could not inadvertently be left unlocked.

The goal, members suggested, is to make the secure behavior the easiest behavior to follow whenever possible.

Reinforce Classroom Door Policies Through Staff Training

Members also described incorporating closed-and-locked door expectations into regular school safety training rather than treating them as a one-time policy announcement.

One school safety leader said the district's locked-door policy had existed before he arrived, but compliance was not routinely monitored or enforced. He began emphasizing the requirement during annual active assailant training and conducting spot checks to determine whether doors were actually secured.

Establish Classroom Door Policies and Accountability

While several NCSSD members emphasized education and staff involvement, others noted that districts eventually have to establish a clear expectation and determine how they will respond when that expectation is repeatedly ignored.

One member said years of pushback ultimately led them to bring the issue before the school board, which adopted a formal policy.

Other districts have established progressive accountability processes. One NCSSD member described an approach that begins with a reminder and discussion about why the security requirement matters. Continued violations are brought to the employee's administrator, while repeated noncompliance is documented and eventually referred to human resources for potential disciplinary action.

The member emphasized documenting the date, time, and location of violations as well as the education, coaching, and administrative intervention that occurred before discipline was considered.

In some states, keeping classroom doors secured is more than a local policy decision. Florida law requires classrooms and other instructional spaces to be locked to prevent entry while occupied by students, with exceptions including class changes. If a classroom must remain open or unlocked for another reason, it generally must be actively staffed at the door. State law also requires school boards and charter school governing boards to adopt progressive discipline policies for instructional and administrative personnel who knowingly violate school safety requirements.

Classroom Door Security Must Also Account for Life Safety

Keeping classroom doors secured does not mean that every locking or barricade method is appropriate.

The National Association of State Fire Marshals (NASFM) has emphasized that classroom security must be balanced with fire, life safety, and accessibility requirements. Its classroom door security guidance recommends that doors be lockable from inside the classroom without requiring the door to be opened, while still allowing occupants to exit without a key, tool, special knowledge or unusual effort.

NASFM also recommends that classroom doors remain capable of being unlocked from outside the room, an important consideration for law enforcement and other emergency responders who may need to gain access during an emergency.

Those considerations were also raised in the NCSSD discussion. One member cautioned that districts implementing locked-door policies should have a plan for how law enforcement will access both exterior and interior doors during an emergency. Another member said their local police department keeps school master keys and access cards secured in patrol vehicles and inventories the keys annually.

School safety leaders should also be cautious about solutions that interfere with normal door operation. NASFM has warned that some aftermarket barricade devices and security locks can compromise life safety or prevent access from outside the classroom.

Ultimately, the goal is not simply to make a classroom door difficult to open. It is to ensure the door can be quickly and reliably secured against an outside threat while still allowing safe egress and emergency access.

Improving Classroom Door Security Through Everyday Practice

The research and lessons from past school shootings make a strong case for keeping classroom doors closed, locked and functioning as intended. But as the recent NCSSD discussion illustrates, having the right hardware or adopting a policy does not automatically translate into consistent practice.

For school leaders, implementation may require addressing the everyday barriers to keeping doors secured, involving educators in developing workable procedures, reinforcing expectations through training, and determining how compliance will be monitored.

Several NCSSD members noted that practices that initially generated resistance eventually became routine. Others emphasized that demonstrations and real-world examples helped staff better understand why the expectation mattered.

As one member put it, “The human factor is always the toughest variable.”

“The best process is only as good as the training and the people entrusted with its success.”