diff --git a/modules/search-query/src/main/scala/io/renku/search/query/Field.scala b/modules/search-query/src/main/scala/io/renku/search/query/Field.scala
index 65d855aa..96ae84a2 100644
--- a/modules/search-query/src/main/scala/io/renku/search/query/Field.scala
+++ b/modules/search-query/src/main/scala/io/renku/search/query/Field.scala
@@ -30,6 +30,7 @@ enum Field:
   case Type
   case Role
   case Keyword
+  case Namespace
 
   val name: String = Strings.lowerFirst(productPrefix)
 
diff --git a/modules/search-query/src/main/scala/io/renku/search/query/FieldTerm.scala b/modules/search-query/src/main/scala/io/renku/search/query/FieldTerm.scala
index 33cf9339..2820821d 100644
--- a/modules/search-query/src/main/scala/io/renku/search/query/FieldTerm.scala
+++ b/modules/search-query/src/main/scala/io/renku/search/query/FieldTerm.scala
@@ -20,6 +20,7 @@ package io.renku.search.query
 
 import cats.data.NonEmptyList
 
+import io.renku.search.model.Namespace
 import io.renku.search.model.projects.Visibility
 import io.renku.search.model.{EntityType, Keyword, MemberRole}
 
@@ -39,6 +40,8 @@ enum FieldTerm(val field: Field, val cmp: Comparison):
       extends FieldTerm(Field.Role, Comparison.Is)
   case KeywordIs(values: NonEmptyList[Keyword])
       extends FieldTerm(Field.Keyword, Comparison.Is)
+  case NamespaceIs(values: NonEmptyList[Namespace])
+      extends FieldTerm(Field.Namespace, Comparison.Is)
 
   private[query] def asString =
     val value = this match
@@ -55,6 +58,7 @@ enum FieldTerm(val field: Field, val cmp: Comparison):
       case CreatedByIs(values) => FieldTerm.nelToString(values)
       case RoleIs(values)      => FieldTerm.nelToString(values.map(_.name))
       case KeywordIs(values)   => FieldTerm.nelToString(values.map(_.value))
+      case NamespaceIs(values) => FieldTerm.nelToString(values.map(_.value))
 
     s"${field.name}${cmp.asString}${value}"
 
diff --git a/modules/search-query/src/main/scala/io/renku/search/query/parse/QueryParser.scala b/modules/search-query/src/main/scala/io/renku/search/query/parse/QueryParser.scala
index f19d0b10..6f4b2089 100644
--- a/modules/search-query/src/main/scala/io/renku/search/query/parse/QueryParser.scala
+++ b/modules/search-query/src/main/scala/io/renku/search/query/parse/QueryParser.scala
@@ -21,8 +21,8 @@ package io.renku.search.query.parse
 import cats.data.NonEmptyList
 import cats.parse.{Parser as P, Parser0 as P0}
 
+import io.renku.search.model.*
 import io.renku.search.model.projects.Visibility
-import io.renku.search.model.{EntityType, Keyword, MemberRole}
 import io.renku.search.query.*
 
 private[query] object QueryParser {
@@ -106,6 +106,7 @@ private[query] object QueryParser {
     ((field <* is) ~ values).map { case (f, v) =>
       f match
         case Field.Name      => FieldTerm.NameIs(v)
+        case Field.Namespace => FieldTerm.NamespaceIs(v.map(Namespace(_)))
         case Field.Id        => FieldTerm.IdIs(v)
         case Field.Slug      => FieldTerm.SlugIs(v)
         case Field.CreatedBy => FieldTerm.CreatedByIs(v)
diff --git a/modules/search-query/src/test/scala/io/renku/search/query/QueryGenerators.scala b/modules/search-query/src/test/scala/io/renku/search/query/QueryGenerators.scala
index 264155fb..5ce77a83 100644
--- a/modules/search-query/src/test/scala/io/renku/search/query/QueryGenerators.scala
+++ b/modules/search-query/src/test/scala/io/renku/search/query/QueryGenerators.scala
@@ -24,8 +24,8 @@ import cats.Order as CatsOrder
 import cats.data.NonEmptyList
 import cats.syntax.all.*
 
+import io.renku.search.model.*
 import io.renku.search.model.projects.Visibility
-import io.renku.search.model.{CommonGenerators, MemberRole, ModelGenerators}
 import io.renku.search.query.parse.QueryUtil
 import org.scalacheck.Gen
 import org.scalacheck.cats.implicits.*
@@ -121,6 +121,9 @@ object QueryGenerators:
   val nameTerm: Gen[FieldTerm] =
     stringValues.map(FieldTerm.NameIs(_))
 
+  val namespaceTerm: Gen[FieldTerm] =
+    stringValues.map(vs => FieldTerm.NamespaceIs(vs.map(Namespace(_))))
+
   val slugTerm: Gen[FieldTerm] =
     stringValues.map(FieldTerm.SlugIs(_))
 
@@ -157,6 +160,7 @@ object QueryGenerators:
     Gen.oneOf(
       projectIdTerm,
       nameTerm,
+      namespaceTerm,
       slugTerm,
       createdByTerm,
       visibilityTerm,
diff --git a/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/LuceneQueryEncoders.scala b/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/LuceneQueryEncoders.scala
index 8673f326..1b75d465 100644
--- a/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/LuceneQueryEncoders.scala
+++ b/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/LuceneQueryEncoders.scala
@@ -80,6 +80,13 @@ trait LuceneQueryEncoders:
       )
     }
 
+  given namespaceIs[F[_]: Applicative]: SolrTokenEncoder[F, FieldTerm.NamespaceIs] =
+    SolrTokenEncoder.basic { case FieldTerm.NamespaceIs(values) =>
+      SolrQuery(
+        SolrToken.orFieldIs(SolrField.namespace, values.map(SolrToken.fromNamespace))
+      )
+    }
+
   given created[F[_]: Monad]: SolrTokenEncoder[F, FieldTerm.Created] =
     val createdIs = SolrToken.fieldIs(SolrField.creationDate, _)
     SolrTokenEncoder.create[F, FieldTerm.Created] {
diff --git a/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/SolrToken.scala b/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/SolrToken.scala
index 3849951b..5cde85e3 100644
--- a/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/SolrToken.scala
+++ b/modules/search-solr-client/src/main/scala/io/renku/search/solr/query/SolrToken.scala
@@ -64,6 +64,9 @@ object SolrToken:
       case Comparison.GreaterThan => ">"
       case Comparison.LowerThan   => "<"
 
+  def fromNamespace(ns: Namespace): SolrToken =
+    fromString(ns.value)
+
   def contentAll(text: String): SolrToken =
     val terms: Seq[SolrToken] = text.split("\\s+").map(_.trim).toSeq
     s"${SolrField.contentAll.name}:${terms.fuzzy}"
@@ -72,7 +75,7 @@ object SolrToken:
     values.map(fieldIs(field, _)).toList.foldOr
 
   def namespaceIs(ns: Namespace): SolrToken =
-    fieldIs(SolrField.namespace, fromString(ns.value))
+    fieldIs(SolrField.namespace, fromNamespace(ns))
 
   def createdDateIs(date: Instant): SolrToken =
     fieldIs(SolrField.creationDate, fromInstant(date))