diff --git a/func.go b/func.go
index 4fc7e8f..930cee7 100644
--- a/func.go
+++ b/func.go
@@ -20,6 +20,7 @@ package sqlite
 import (
 	"errors"
 	"fmt"
+	"iter"
 	"math"
 	"math/bits"
 	"strconv"
@@ -225,6 +226,32 @@ func (v Value) Type() ColumnType {
 	return ColumnType(lib.Xsqlite3_value_type(v.tls, v.ptrOrType))
 }
 
+// All iterates all values of an IN operator
+// https://www.sqlite.org/c3ref/vtab_in.html
+// https://www.sqlite.org/c3ref/vtab_in_first.html
+func (v Value) All() iter.Seq[Value] {
+	return func(yield func(Value) bool) {
+		if v.tls == nil ||
+			v.ptrOrType == 0 ||
+			ColumnType(lib.Xsqlite3_value_type(v.tls, v.ptrOrType)) != TypeNull {
+			return
+		}
+		ppVal := lib.Xsqlite3_malloc(v.tls, int32(unsafe.Sizeof(uintptr(0))))
+		if ppVal != 0 {
+			defer lib.Xsqlite3_free(v.tls, ppVal)
+		}
+		for rc := ResultCode(lib.Xsqlite3_vtab_in_first(v.tls, v.ptrOrType, ppVal)); rc == ResultOK && *(*uintptr)(unsafe.Pointer(ppVal)) != 0; rc = ResultCode(lib.Xsqlite3_vtab_in_next(v.tls, v.ptrOrType, ppVal)) {
+			// do something with pVal
+			if !yield(Value{
+				tls:       v.tls,
+				ptrOrType: *(*uintptr)(unsafe.Pointer(ppVal)),
+			}) {
+				return
+			}
+		}
+	}
+}
+
 // Conversions follow the table in https://sqlite.org/c3ref/column_blob.html
 
 // Int returns the value as an integer.
diff --git a/go.work.sum b/go.work.sum
index 9daa703..0a0056e 100644
--- a/go.work.sum
+++ b/go.work.sum
@@ -1,17 +1,17 @@
-github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/pprof v0.0.0-20221118152302-e6195bd50e26 h1:Xim43kblpZXfIBQsbuBVKCudVG457BR2GZFIz3uw3hQ=
 github.com/google/pprof v0.0.0-20221118152302-e6195bd50e26/go.mod h1:dDKJzRmX4S37WGHujM7tX//fmj1uioxKzKxz3lo4HJo=
 github.com/google/pprof v0.0.0-20240409012703-83162a5b38cd/go.mod h1:kf6iHlnVGwgKolg33glAes7Yg/8iWP8ukqeldJSO7jw=
+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51/go.mod h1:CzGEWj7cYgsdH8dAjBGEr58BoE7ScuLd+fwFZ44+/x8=
 github.com/mattn/go-sqlite3 v1.14.16 h1:yOQRA0RpS5PFz/oikGwBEqvAWhWg5ufRz4ETLjwpU1Y=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M=
+golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.16.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
-golang.org/x/mod v0.24.0/go.mod h1:IXM97Txy2VM4PJ3gI61r1YEk/gAj6zAHN3AdZt6S9Ww=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
@@ -24,7 +24,6 @@ golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sync v0.14.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -37,6 +36,7 @@ golang.org/x/telemetry v0.0.0-20240521205824-bda55230c457/go.mod h1:pRgIJT+bRLFK
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
 golang.org/x/term v0.22.0/go.mod h1:F3qCibpT5AMpCRfhfT53vVJwhLtIVHhB9XDjfFvnMI4=
+golang.org/x/term v0.32.0/go.mod h1:uZG1FhGx848Sqfsq4/DlJr3xGGsYMu/L5GW4abiaEPQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
@@ -49,7 +49,6 @@ golang.org/x/tools v0.17.0 h1:FvmRgNOcs3kOa+T20R1uhfP9F6HgG2mfxDv1vrx1Htc=
 golang.org/x/tools v0.17.0/go.mod h1:xsh6VxdV005rRVaS6SSAf9oiAqljS7UZUacMZ8Bnsps=
 golang.org/x/tools v0.19.0/go.mod h1:qoJWxmGSIBmAeriMx19ogtrEPrGtDbPK634QFIcLAhc=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
-golang.org/x/tools v0.33.0/go.mod h1:CIJMaWEY88juyUfo7UbgPqbC8rU2OqfAV1h2Qp0oMYI=
 lukechampine.com/uint128 v1.2.0/go.mod h1:c4eWIwlEGaxC/+H1VguhU4PHXNWDCDMUlWdIWl2j1gk=
 modernc.org/cc/v3 v3.41.0/go.mod h1:Ni4zjJYJ04CDOhG7dn640WGfwBzfE0ecX8TyMB0Fv0Y=
 modernc.org/ccgo/v3 v3.17.0/go.mod h1:Sg3fwVpmLvCUTaqEUjiBDAvshIaKDB0RXaf+zgqFu8I=
diff --git a/index_constraint.go b/index_constraint.go
index bf38a3d..d25a775 100644
--- a/index_constraint.go
+++ b/index_constraint.go
@@ -32,6 +32,9 @@ type IndexConstraint struct {
 	RValue Value
 	// RValueKnown indicates whether RValue is set.
 	RValueKnown bool
+	// InOpAllAtOnce is true if the constraint is an IN operator
+	// that can be processed all at once
+	InOpAllAtOnce bool
 }
 
 func (c *IndexConstraint) copyFromC(tls *libc.TLS, infoPtr uintptr, i int32, ppVal uintptr) {
@@ -43,6 +46,12 @@ func (c *IndexConstraint) copyFromC(tls *libc.TLS, infoPtr uintptr, i int32, ppV
 		Usable: src.Fusable != 0,
 	}
 
+	if c.Op == IndexConstraintEq {
+		if lib.Xsqlite3_vtab_in(tls, infoPtr, int32(i), -1) != 0 {
+			c.InOpAllAtOnce = true
+		}
+	}
+
 	const binaryCollation = "BINARY"
 	cCollation := lib.Xsqlite3_vtab_collation(tls, infoPtr, int32(i))
 	if isCStringEqual(cCollation, binaryCollation) {
diff --git a/vtable.go b/vtable.go
index abe0cd8..b7f224a 100644
--- a/vtable.go
+++ b/vtable.go
@@ -252,7 +252,7 @@ func (outputs *IndexOutputs) copyToC(tls *libc.TLS, infoPtr uintptr) error {
 	info := (*lib.Sqlite3_index_info)(unsafe.Pointer(infoPtr))
 
 	aConstraintUsage := info.FaConstraintUsage
-	for _, u := range outputs.ConstraintUsage {
+	for i, u := range outputs.ConstraintUsage {
 		ptr := (*lib.Sqlite3_index_constraint_usage)(unsafe.Pointer(aConstraintUsage))
 		ptr.FargvIndex = int32(u.ArgvIndex)
 		if u.Omit {
@@ -260,6 +260,9 @@ func (outputs *IndexOutputs) copyToC(tls *libc.TLS, infoPtr uintptr) error {
 		} else {
 			ptr.Fomit = 0
 		}
+		if u.InOpAllAtOnce {
+			lib.Xsqlite3_vtab_in(tls, infoPtr, int32(i), 1)
+		}
 		aConstraintUsage += unsafe.Sizeof(lib.Sqlite3_index_constraint_usage{})
 	}
 	info.FidxNum = outputs.ID.Num
@@ -306,6 +309,9 @@ type IndexConstraintUsage struct {
 	// SQLite will always double-check that rows satisfy the constraint if Omit is false,
 	// but may skip this check if Omit is true.
 	Omit bool
+	// Set InOpAllAtOnce to true if the constraint is an IN operator and the
+	// Filter method should receive all values at once.
+	InOpAllAtOnce bool
 }
 
 // IndexID is a virtual table index identifier.
diff --git a/vtable_example_test.go b/vtable_example_test.go
index 133c389..15ac6ab 100644
--- a/vtable_example_test.go
+++ b/vtable_example_test.go
@@ -38,6 +38,19 @@ func ExampleVTable() {
 		log.Fatal(err)
 	}
 
+	err = sqlitex.ExecuteTransient(
+		conn,
+		`SELECT a, b FROM templatevtab WHERE a IN (1001, 1003, 1005, 1007, 1009) ORDER BY rowid;`,
+		&sqlitex.ExecOptions{
+			ResultFunc: func(stmt *sqlite.Stmt) error {
+				fmt.Printf("%4d, %4d\n", stmt.ColumnInt(0), stmt.ColumnInt(1))
+				return nil
+			},
+		},
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
 	// Output:
 	// 1001, 2001
 	// 1002, 2002
@@ -49,6 +62,11 @@ func ExampleVTable() {
 	// 1008, 2008
 	// 1009, 2009
 	// 1010, 2010
+	// 1001, 2001
+	// 1003, 2003
+	// 1005, 2005
+	// 1007, 2007
+	// 1009, 2009
 }
 
 type templatevtab struct{}
@@ -66,10 +84,22 @@ func templatevtabConnect(c *sqlite.Conn, opts *sqlite.VTableConnectOptions) (sql
 	return vtab, cfg, nil
 }
 
-func (vt *templatevtab) BestIndex(*sqlite.IndexInputs) (*sqlite.IndexOutputs, error) {
+func (vt *templatevtab) BestIndex(in *sqlite.IndexInputs) (*sqlite.IndexOutputs, error) {
+
+	constraintUsage := make([]sqlite.IndexConstraintUsage, len(in.Constraints))
+
+	argvIndex := 1
+	for i, c := range in.Constraints {
+		if c.InOpAllAtOnce {
+			constraintUsage[i].ArgvIndex = argvIndex
+			constraintUsage[i].InOpAllAtOnce = true
+			argvIndex++
+		}
+	}
 	return &sqlite.IndexOutputs{
-		EstimatedCost: 10,
-		EstimatedRows: 10,
+		ConstraintUsage: constraintUsage,
+		EstimatedCost:   10,
+		EstimatedRows:   10,
 	}, nil
 }
 
@@ -86,10 +116,17 @@ func (vt *templatevtab) Destroy() error {
 }
 
 type templatevtabCursor struct {
-	rowid int64
+	rowid  int64
+	inVals []int64
 }
 
 func (cur *templatevtabCursor) Filter(id sqlite.IndexID, argv []sqlite.Value) error {
+	for _, v := range argv {
+		for vv := range v.All() {
+			cur.inVals = append(cur.inVals, vv.Int64())
+		}
+	}
+
 	cur.rowid = 1
 	return nil
 }
@@ -102,8 +139,14 @@ func (cur *templatevtabCursor) Next() error {
 func (cur *templatevtabCursor) Column(i int, noChange bool) (sqlite.Value, error) {
 	switch i {
 	case templatevarColumnA:
+		if len(cur.inVals) > 0 {
+			return sqlite.IntegerValue(cur.inVals[cur.rowid-1]), nil
+		}
 		return sqlite.IntegerValue(1000 + cur.rowid), nil
 	case templatevarColumnB:
+		if len(cur.inVals) > 0 {
+			return sqlite.IntegerValue(1000 + cur.inVals[cur.rowid-1]), nil
+		}
 		return sqlite.IntegerValue(2000 + cur.rowid), nil
 	default:
 		panic("unreachable")
@@ -115,6 +158,9 @@ func (cur *templatevtabCursor) RowID() (int64, error) {
 }
 
 func (cur *templatevtabCursor) EOF() bool {
+	if len(cur.inVals) > 0 {
+		return int(cur.rowid) > len(cur.inVals)
+	}
 	return cur.rowid > 10
 }