diff --git a/enforcer.go b/enforcer.go
index ff8c5431f..f82a2c5d7 100644
--- a/enforcer.go
+++ b/enforcer.go
@@ -31,7 +31,8 @@ import (
 	defaultrolemanager "github.com/casbin/casbin/v3/rbac/default-role-manager"
 	"github.com/casbin/casbin/v3/util"
 
-	"github.com/casbin/govaluate"
+	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/vm"
 )
 
 // Enforcer is the main interface for authorization enforcement and policy management.
@@ -737,6 +738,8 @@ func (e *Enforcer) enforce(matcher string, explains *[]string, rvals ...interfac
 		// For custom matchers provided at runtime, escape backslashes in string literals
 		expString = util.EscapeStringLiterals(util.RemoveComments(util.EscapeAssertion(matcher)))
 	}
+	// Convert govaluate IN operator syntax to expr syntax
+	expString = util.ConvertInOperatorSyntax(expString)
 
 	rTokens := make(map[string]int, len(e.model["r"][rType].Tokens))
 	for i, token := range e.model["r"][rType].Tokens {
@@ -777,8 +780,8 @@ func (e *Enforcer) enforce(matcher string, explains *[]string, rvals ...interfac
 	if hasEval {
 		functions["eval"] = generateEvalFunction(functions, &parameters)
 	}
-	var expression *govaluate.EvaluableExpression
-	expression, err = e.getAndStoreMatcherExpression(hasEval, expString, functions)
+	var expression *vm.Program
+	expression, err = e.getAndStoreMatcherExpression(hasEval, expString, functions, rTokens, pTokens)
 	if err != nil {
 		return false, err
 	}
@@ -813,7 +816,13 @@ func (e *Enforcer) enforce(matcher string, explains *[]string, rvals ...interfac
 
 			parameters.pVals = pvals
 
-			result, err := expression.Eval(parameters)
+			// Create environment with functions and parameters
+			env := parameters.ToMap()
+			for k, v := range functions {
+				env[k] = v
+			}
+
+			result, err := expr.Run(expression, env)
 			// log.LogPrint("Result: ", result)
 
 			if err != nil {
@@ -871,7 +880,13 @@ func (e *Enforcer) enforce(matcher string, explains *[]string, rvals ...interfac
 
 		parameters.pVals = make([]string, len(parameters.pTokens))
 
-		result, err := expression.Eval(parameters)
+		// Create environment with functions and parameters
+		env := parameters.ToMap()
+		for k, v := range functions {
+			env[k] = v
+		}
+
+		result, err := expr.Run(expression, env)
 
 		if err != nil {
 			return false, err
@@ -904,15 +919,21 @@ func (e *Enforcer) enforce(matcher string, explains *[]string, rvals ...interfac
 	return result, nil
 }
 
-func (e *Enforcer) getAndStoreMatcherExpression(hasEval bool, expString string, functions map[string]govaluate.ExpressionFunction) (*govaluate.EvaluableExpression, error) {
-	var expression *govaluate.EvaluableExpression
+func (e *Enforcer) getAndStoreMatcherExpression(hasEval bool, expString string, functions map[string]interface{}, rTokens, pTokens map[string]int) (*vm.Program, error) {
+	var expression *vm.Program
 	var err error
 	var cachedExpression, isPresent = e.matcherMap.Load(expString)
 
 	if !hasEval && isPresent {
-		expression = cachedExpression.(*govaluate.EvaluableExpression)
+		expression = cachedExpression.(*vm.Program)
 	} else {
-		expression, err = govaluate.NewEvaluableExpressionWithFunctions(expString, functions)
+		// Create environment with functions
+		env := make(map[string]interface{})
+		for k, v := range functions {
+			env[k] = v
+		}
+		// Compile with AllowUndefinedVariables to support ABAC and dynamic parameter access
+		expression, err = expr.Compile(expString, expr.Env(env), expr.AllowUndefinedVariables())
 		if err != nil {
 			return nil, err
 		}
@@ -1041,7 +1062,24 @@ type enforceParameters struct {
 	pVals   []string
 }
 
-// implements govaluate.Parameters.
+// ToMap converts enforceParameters to a map suitable for expr evaluation.
+func (p enforceParameters) ToMap() map[string]interface{} {
+	env := make(map[string]interface{})
+
+	// Add r parameters
+	for token, index := range p.rTokens {
+		env[token] = p.rVals[index]
+	}
+
+	// Add p parameters
+	for token, index := range p.pTokens {
+		env[token] = p.pVals[index]
+	}
+
+	return env
+}
+
+// Get implements parameter access for backward compatibility.
 func (p enforceParameters) Get(name string) (interface{}, error) {
 	if name == "" {
 		return nil, nil
@@ -1065,7 +1103,7 @@ func (p enforceParameters) Get(name string) (interface{}, error) {
 	}
 }
 
-func generateEvalFunction(functions map[string]govaluate.ExpressionFunction, parameters *enforceParameters) govaluate.ExpressionFunction {
+func generateEvalFunction(functions map[string]interface{}, parameters *enforceParameters) func(args ...interface{}) (interface{}, error) {
 	return func(args ...interface{}) (interface{}, error) {
 		if len(args) != 1 {
 			return nil, fmt.Errorf("function eval(subrule string) expected %d arguments, but got %d", 1, len(args))
@@ -1076,10 +1114,23 @@ func generateEvalFunction(functions map[string]govaluate.ExpressionFunction, par
 			return nil, errors.New("argument of eval(subrule string) must be a string")
 		}
 		expression = util.EscapeAssertion(expression)
-		expr, err := govaluate.NewEvaluableExpressionWithFunctions(expression, functions)
+		// Convert IN operator syntax for compatibility
+		expression = util.ConvertInOperatorSyntax(expression)
+		// Create environment with functions for compilation
+		env := make(map[string]interface{})
+		for k, v := range functions {
+			env[k] = v
+		}
+		// Compile with AllowUndefinedVariables to support dynamic parameter access
+		program, err := expr.Compile(expression, expr.Env(env), expr.AllowUndefinedVariables())
 		if err != nil {
 			return nil, fmt.Errorf("error while parsing eval parameter: %s, %s", expression, err.Error())
 		}
-		return expr.Eval(parameters)
+		// Create environment with parameters and functions for evaluation
+		evalEnv := parameters.ToMap()
+		for k, v := range functions {
+			evalEnv[k] = v
+		}
+		return expr.Run(program, evalEnv)
 	}
 }
diff --git a/enforcer_interface.go b/enforcer_interface.go
index 733653187..cea7dab49 100644
--- a/enforcer_interface.go
+++ b/enforcer_interface.go
@@ -19,7 +19,6 @@ import (
 	"github.com/casbin/casbin/v3/model"
 	"github.com/casbin/casbin/v3/persist"
 	"github.com/casbin/casbin/v3/rbac"
-	"github.com/casbin/govaluate"
 )
 
 var _ IEnforcer = &Enforcer{}
@@ -138,7 +137,7 @@ type IEnforcer interface {
 	RemoveNamedGroupingPolicy(ptype string, params ...interface{}) (bool, error)
 	RemoveNamedGroupingPolicies(ptype string, rules [][]string) (bool, error)
 	RemoveFilteredNamedGroupingPolicy(ptype string, fieldIndex int, fieldValues ...string) (bool, error)
-	AddFunction(name string, function govaluate.ExpressionFunction)
+	AddFunction(name string, function interface{})
 
 	UpdatePolicy(oldPolicy []string, newPolicy []string) (bool, error)
 	UpdatePolicies(oldPolicies [][]string, newPolicies [][]string) (bool, error)
diff --git a/enforcer_synced.go b/enforcer_synced.go
index 89bbe5dae..6263c3f58 100644
--- a/enforcer_synced.go
+++ b/enforcer_synced.go
@@ -19,8 +19,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/casbin/govaluate"
-
 	"github.com/casbin/casbin/v3/persist"
 	"github.com/casbin/casbin/v3/rbac"
 )
@@ -631,7 +629,7 @@ func (e *SyncedEnforcer) RemoveFilteredNamedGroupingPolicy(ptype string, fieldIn
 }
 
 // AddFunction adds a customized function.
-func (e *SyncedEnforcer) AddFunction(name string, function govaluate.ExpressionFunction) {
+func (e *SyncedEnforcer) AddFunction(name string, function interface{}) {
 	e.m.Lock()
 	defer e.m.Unlock()
 	e.Enforcer.AddFunction(name, function)
diff --git a/go.mod b/go.mod
index c46f727d3..331183102 100644
--- a/go.mod
+++ b/go.mod
@@ -2,7 +2,7 @@ module github.com/casbin/casbin/v3
 
 require (
 	github.com/bmatcuk/doublestar/v4 v4.6.1
-	github.com/casbin/govaluate v1.3.0
+	github.com/expr-lang/expr v1.17.7
 	github.com/google/uuid v1.6.0
 )
 
diff --git a/go.sum b/go.sum
index 2f3a1c775..3c2d6b86f 100644
--- a/go.sum
+++ b/go.sum
@@ -1,6 +1,6 @@
 github.com/bmatcuk/doublestar/v4 v4.6.1 h1:FH9SifrbvJhnlQpztAx++wlkk70QBf0iBWDwNy7PA4I=
 github.com/bmatcuk/doublestar/v4 v4.6.1/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
-github.com/casbin/govaluate v1.3.0 h1:VA0eSY0M2lA86dYd5kPPuNZMUD9QkWnOCnavGrw9myc=
-github.com/casbin/govaluate v1.3.0/go.mod h1:G/UnbIjZk/0uMNaLwZZmFQrR72tYRZWQkO70si/iR7A=
+github.com/expr-lang/expr v1.17.7 h1:Q0xY/e/2aCIp8g9s/LGvMDCC5PxYlvHgDZRQ4y16JX8=
+github.com/expr-lang/expr v1.17.7/go.mod h1:8/vRC7+7HBzESEqt5kKpYXxrxkr31SaO8r40VO/1IT4=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
diff --git a/management_api.go b/management_api.go
index 7a8f768ee..fc47c44f6 100644
--- a/management_api.go
+++ b/management_api.go
@@ -21,7 +21,9 @@ import (
 
 	"github.com/casbin/casbin/v3/constant"
 	"github.com/casbin/casbin/v3/util"
-	"github.com/casbin/govaluate"
+
+	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/vm"
 )
 
 // GetAllSubjects gets the list of subjects that show up in the current policy.
@@ -159,10 +161,18 @@ func (e *Enforcer) GetFilteredNamedPolicyWithMatcher(ptype string, matcher strin
 	} else {
 		expString = util.RemoveComments(util.EscapeAssertion(matcher))
 	}
+	// Convert govaluate IN operator syntax to expr syntax
+	expString = util.ConvertInOperatorSyntax(expString)
 
-	var expression *govaluate.EvaluableExpression
+	var expression *vm.Program
 
-	expression, err = govaluate.NewEvaluableExpressionWithFunctions(expString, functions)
+	// Create environment with functions
+	env := make(map[string]interface{})
+	for k, v := range functions {
+		env[k] = v
+	}
+	// Compile with AllowUndefinedVariables to support dynamic parameter access
+	expression, err = expr.Compile(expString, expr.Env(env), expr.AllowUndefinedVariables())
 	if err != nil {
 		return res, err
 	}
@@ -188,7 +198,13 @@ func (e *Enforcer) GetFilteredNamedPolicyWithMatcher(ptype string, matcher strin
 
 			parameters.pVals = pvals
 
-			result, err := expression.Eval(parameters)
+			// Create environment with functions and parameters
+			evalEnv := parameters.ToMap()
+			for k, v := range functions {
+				evalEnv[k] = v
+			}
+
+			result, err := expr.Run(expression, evalEnv)
 
 			if err != nil {
 				return res, err
@@ -480,7 +496,7 @@ func (e *Enforcer) RemoveFilteredNamedGroupingPolicy(ptype string, fieldIndex in
 }
 
 // AddFunction adds a customized function.
-func (e *Enforcer) AddFunction(name string, function govaluate.ExpressionFunction) {
+func (e *Enforcer) AddFunction(name string, function interface{}) {
 	e.fm.AddFunction(name, function)
 }
 
diff --git a/model/function.go b/model/function.go
index 956c94b9d..a1db70f42 100644
--- a/model/function.go
+++ b/model/function.go
@@ -18,7 +18,6 @@ import (
 	"sync"
 
 	"github.com/casbin/casbin/v3/util"
-	"github.com/casbin/govaluate"
 )
 
 // FunctionMap represents the collection of Function.
@@ -26,10 +25,8 @@ type FunctionMap struct {
 	fns *sync.Map
 }
 
-// [string]govaluate.ExpressionFunction
-
 // AddFunction adds an expression function.
-func (fm *FunctionMap) AddFunction(name string, function govaluate.ExpressionFunction) {
+func (fm *FunctionMap) AddFunction(name string, function interface{}) {
 	fm.fns.LoadOrStore(name, function)
 }
 
@@ -54,11 +51,11 @@ func LoadFunctionMap() FunctionMap {
 }
 
 // GetFunctions return a map with all the functions.
-func (fm *FunctionMap) GetFunctions() map[string]govaluate.ExpressionFunction {
-	ret := make(map[string]govaluate.ExpressionFunction)
+func (fm *FunctionMap) GetFunctions() map[string]interface{} {
+	ret := make(map[string]interface{})
 
 	fm.fns.Range(func(k interface{}, v interface{}) bool {
-		ret[k.(string)] = v.(govaluate.ExpressionFunction)
+		ret[k.(string)] = v
 		return true
 	})
 
diff --git a/util/builtin_operators.go b/util/builtin_operators.go
index 37d9cb5bf..6a99cf774 100644
--- a/util/builtin_operators.go
+++ b/util/builtin_operators.go
@@ -26,8 +26,6 @@ import (
 	"github.com/bmatcuk/doublestar/v4"
 
 	"github.com/casbin/casbin/v3/rbac"
-
-	"github.com/casbin/govaluate"
 )
 
 var (
@@ -402,10 +400,10 @@ func GlobMatchFunc(args ...interface{}) (interface{}, error) {
 }
 
 // GenerateGFunction is the factory method of the g(_, _[, _]) function.
-func GenerateGFunction(rm rbac.RoleManager) govaluate.ExpressionFunction {
+func GenerateGFunction(rm rbac.RoleManager) func(args ...interface{}) (interface{}, error) {
 	memorized := sync.Map{}
 	return func(args ...interface{}) (interface{}, error) {
-		// Like all our other govaluate functions, all args are strings.
+		// Like all our other expression functions, all args are strings.
 
 		// Allocate and generate a cache key from the arguments...
 		total := len(args)
@@ -445,9 +443,9 @@ func GenerateGFunction(rm rbac.RoleManager) govaluate.ExpressionFunction {
 }
 
 // GenerateConditionalGFunction is the factory method of the g(_, _[, _]) function with conditions.
-func GenerateConditionalGFunction(crm rbac.ConditionalRoleManager) govaluate.ExpressionFunction {
+func GenerateConditionalGFunction(crm rbac.ConditionalRoleManager) func(args ...interface{}) (interface{}, error) {
 	return func(args ...interface{}) (interface{}, error) {
-		// Like all our other govaluate functions, all args are strings.
+		// Like all our other expression functions, all args are strings.
 		var hasLink bool
 
 		name1, name2 := args[0].(string), args[1].(string)
diff --git a/util/util.go b/util/util.go
index b72823a4c..0387d36ea 100644
--- a/util/util.go
+++ b/util/util.go
@@ -311,6 +311,22 @@ func EscapeStringLiterals(expr string) string {
 	return result.String()
 }
 
+// ConvertInOperatorSyntax converts govaluate's IN operator syntax to expr's syntax.
+// Changes: `x in ('a', 'b')` to `x in ['a', 'b']`
+// Also handles: `x IN ('a', 'b')` (case insensitive).
+// And: `x IN array` to `x in array`.
+func ConvertInOperatorSyntax(expression string) string {
+	// First, replace all IN/In/iN with lowercase 'in' (case insensitive)
+	// Use word boundaries to avoid replacing IN in the middle of identifiers.
+	reCase := regexp.MustCompile(`(?i)\bIN\b`)
+	expression = reCase.ReplaceAllString(expression, "in")
+
+	// Then, replace `in (...)` with `in [...]`
+	// This handles simple cases but may not work with deeply nested parentheses.
+	re := regexp.MustCompile(`\bin\s*\(([^)]+)\)`)
+	return re.ReplaceAllString(expression, "in [$1]")
+}
+
 func RemoveDuplicateElement(s []string) []string {
 	result := make([]string, 0, len(s))
 	temp := map[string]struct{}{}