diff --git a/compiler/kernel/vexpr.go b/compiler/kernel/vexpr.go
index 833caf9ef4..eeb9137aee 100644
--- a/compiler/kernel/vexpr.go
+++ b/compiler/kernel/vexpr.go
@@ -100,8 +100,8 @@ func (b *Builder) compileVamBinary(e *dag.BinaryExpr) (vamexpr.Evaluator, error)
 		return vamexpr.NewLogicalAnd(b.zctx(), lhs, rhs), nil
 	case "or":
 		return vamexpr.NewLogicalOr(b.zctx(), lhs, rhs), nil
-	//case "in": XXX TBD
-	//	return vamexpr.NewIn(b.zctx(), lhs, rhs), nil
+	case "in":
+		return vamexpr.NewIn(b.zctx(), lhs, rhs), nil
 	case "==", "!=", "<", "<=", ">", ">=":
 		return vamexpr.NewCompare(b.zctx(), lhs, rhs, op), nil
 	case "+", "-", "*", "/", "%":
diff --git a/runtime/vam/expr/logic.go b/runtime/vam/expr/logic.go
index cf4da97b29..c229db0e12 100644
--- a/runtime/vam/expr/logic.go
+++ b/runtime/vam/expr/logic.go
@@ -1,6 +1,8 @@
 package expr
 
 import (
+	"slices"
+
 	"github.com/brimdata/super"
 	"github.com/brimdata/super/vector"
 )
@@ -177,6 +179,18 @@ func toBool(vec vector.Any) *vector.Bool {
 		} else {
 			return vector.NewBoolEmpty(vec.Len(), vec.Nulls)
 		}
+	case *vector.Dynamic:
+		nulls := vector.NewBoolEmpty(vec.Len(), nil)
+		out := vector.NewBoolEmpty(vec.Len(), nulls)
+		for i := range vec.Len() {
+			v, null := vector.BoolValue(vec, i)
+			if null {
+				nulls.Set(i)
+			} else if v {
+				out.Set(i)
+			}
+		}
+		return out
 	case *vector.Bool:
 		return vec
 	default:
@@ -191,3 +205,90 @@ func trueBool(n uint32) *vector.Bool {
 	}
 	return vec
 }
+
+type In struct {
+	zctx *super.Context
+	lhs  Evaluator
+	rhs  Evaluator
+	eq   *Compare
+}
+
+func NewIn(zctx *super.Context, lhs, rhs Evaluator) *In {
+	return &In{zctx, lhs, rhs, NewCompare(zctx, nil, nil, "==")}
+}
+
+func (i *In) Eval(this vector.Any) vector.Any {
+	return vector.Apply(true, i.eval, i.lhs.Eval(this), i.rhs.Eval(this))
+}
+
+func (i *In) eval(vecs ...vector.Any) vector.Any {
+	lhs, rhs := vecs[0], vecs[1]
+	if lhs.Type().Kind() == super.ErrorKind {
+		return lhs
+	}
+	if rhs.Type().Kind() == super.ErrorKind {
+		return rhs
+	}
+	return i.evalResursive(lhs, rhs)
+}
+
+func (i *In) evalResursive(vecs ...vector.Any) vector.Any {
+	lhs, rhs := vecs[0], vecs[1]
+	rhs = vector.Under(rhs)
+	var index []uint32
+	if view, ok := rhs.(*vector.View); ok {
+		rhs = view.Any
+		index = view.Index
+	}
+	switch rhs := rhs.(type) {
+	case *vector.Record:
+		out := vector.NewBoolEmpty(lhs.Len(), nil)
+		for _, f := range rhs.Fields {
+			if index != nil {
+				f = vector.NewView(f, index)
+			}
+			out = vector.Or(out, toBool(i.evalResursive(lhs, f)))
+		}
+		return out
+	case *vector.Array:
+		return i.evalForList(lhs, rhs.Values, rhs.Offsets, index)
+	case *vector.Set:
+		return i.evalForList(lhs, rhs.Values, rhs.Offsets, index)
+	case *vector.Map:
+		return vector.Or(i.evalForList(lhs, rhs.Keys, rhs.Offsets, index),
+			i.evalForList(lhs, rhs.Values, rhs.Offsets, index))
+	case *vector.Union:
+		return vector.Apply(true, i.evalResursive, lhs, rhs)
+	case *vector.Error:
+		return i.evalResursive(lhs, rhs.Vals)
+	default:
+		return i.eq.eval(lhs, rhs)
+	}
+}
+
+func (i *In) evalForList(lhs, rhs vector.Any, offsets, index []uint32) *vector.Bool {
+	out := vector.NewBoolEmpty(lhs.Len(), nil)
+	var lhsIndex, rhsIndex []uint32
+	for j := range lhs.Len() {
+		if index != nil {
+			j = index[j]
+		}
+		start, end := offsets[j], offsets[j+1]
+		if start == end {
+			continue
+		}
+		n := end - start
+		lhsIndex = slices.Grow(lhsIndex[:0], int(n))[:n]
+		rhsIndex = slices.Grow(rhsIndex[:0], int(n))[:n]
+		for k := range n {
+			lhsIndex[k] = k
+			rhsIndex[k] = k + start
+		}
+		lhsView := vector.NewView(lhs, lhsIndex)
+		rhsView := vector.NewView(rhs, rhsIndex)
+		if toBool(i.evalResursive(lhsView, rhsView)).TrueCount() > 0 {
+			out.Set(j)
+		}
+	}
+	return out
+}
diff --git a/runtime/sam/expr/ztests/in-field.yaml b/runtime/ztests/expr/in-field.yaml
similarity index 92%
rename from runtime/sam/expr/ztests/in-field.yaml
rename to runtime/ztests/expr/in-field.yaml
index 52b1619c94..fcc1b68ef7 100644
--- a/runtime/sam/expr/ztests/in-field.yaml
+++ b/runtime/ztests/expr/in-field.yaml
@@ -1,5 +1,7 @@
 zed: 2 in a
 
+vector: true
+
 input: |
   {a:[1(uint32),2(uint32)]}
   {a:[1(uint32)]}
diff --git a/runtime/ztests/expr/in.yaml b/runtime/ztests/expr/in.yaml
new file mode 100644
index 0000000000..a6be236ae6
--- /dev/null
+++ b/runtime/ztests/expr/in.yaml
@@ -0,0 +1,28 @@
+zed: |
+  yield [1 in this, 9 in this]
+
+vector: true
+
+input: |
+  1
+  {a:1}
+  [0,1,2]
+  |[0,1,2]|
+  |{1:null}|
+  |{null:1}|
+  1((int64,string))
+  {a:[0,1]([(int64,string)])}
+  [error(0),error(1)]
+  error(0)
+
+output: |
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [true,false]
+  [error(0),error(0)]
diff --git a/vector/bool.go b/vector/bool.go
index 289d24720c..ed3cac6671 100644
--- a/vector/bool.go
+++ b/vector/bool.go
@@ -146,13 +146,16 @@ func And(a, b *Bool) *Bool {
 
 // BoolValue returns the value of slot in vec if the value is a Boolean.  It
 // returns false otherwise.
-func BoolValue(vec Any, slot uint32) bool {
+func BoolValue(vec Any, slot uint32) (bool, bool) {
 	switch vec := Under(vec).(type) {
 	case *Bool:
-		return vec.Value(slot)
+		return vec.Value(slot), vec.Nulls.Value(slot)
 	case *Const:
-		return vec.Value().Ptr().AsBool()
+		return vec.Value().Ptr().AsBool(), vec.Nulls.Value(slot)
 	case *Dict:
+		if vec.Nulls.Value(slot) {
+			return false, true
+		}
 		return BoolValue(vec.Any, uint32(vec.Index[slot]))
 	case *Dynamic:
 		tag := vec.Tags[slot]
@@ -160,7 +163,7 @@ func BoolValue(vec Any, slot uint32) bool {
 	case *View:
 		return BoolValue(vec.Any, vec.Index[slot])
 	}
-	return false
+	panic(vec)
 }
 
 func NullsOf(v Any) *Bool {