diff --git a/Sources/PklSwift/EvaluatorOptions.swift b/Sources/PklSwift/EvaluatorOptions.swift
index 065bcb6..849591c 100644
--- a/Sources/PklSwift/EvaluatorOptions.swift
+++ b/Sources/PklSwift/EvaluatorOptions.swift
@@ -244,7 +244,7 @@ extension EvaluatorOptions {
     public func withModuleReader(_ reader: ModuleReader) -> EvaluatorOptions {
         var options = self
         var allowedModules = options.allowedModules ?? []
-        allowedModules.append(reader.scheme)
+        allowedModules.append(quoteRegex(reader.scheme+":"))
         var moduleReaders = options.moduleReaders ?? []
         moduleReaders.append(reader)
         options.allowedModules = allowedModules
@@ -256,7 +256,7 @@ extension EvaluatorOptions {
     public func withResourceReader(_ reader: ResourceReader) -> EvaluatorOptions {
         var options = self
         var allowedResources = options.allowedResources ?? []
-        allowedResources.append(reader.scheme)
+        allowedResources.append(quoteRegex(reader.scheme+":"))
         var resourceReaders = options.resourceReaders ?? []
         resourceReaders.append(reader)
         options.allowedResources = allowedResources
diff --git a/Sources/PklSwift/Utils.swift b/Sources/PklSwift/Utils.swift
index 092a981..a949ee6 100644
--- a/Sources/PklSwift/Utils.swift
+++ b/Sources/PklSwift/Utils.swift
@@ -118,3 +118,14 @@ public struct OptionalDictionaryKey<Wrapped>: Hashable, Decodable, CodingKeyRepr
         fatalError("cannot initialize OptionalDictionaryKey from CodingKey")
     }
 }
+
+private let regexSpecialCharacters = CharacterSet(charactersIn: #"\.+*?()|[]{}^$"#)
+
+func quoteRegex(_ pattern: String) -> String {
+    if pattern.rangeOfCharacter(from: regexSpecialCharacters) == nil {
+        return pattern
+    }
+
+    // return quoted pattern per https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html
+    return #"\Q\#(pattern)\E"#
+}
diff --git a/Tests/PklSwiftTests/EvaluatorTest.swift b/Tests/PklSwiftTests/EvaluatorTest.swift
index 846cd4c..042ae6c 100644
--- a/Tests/PklSwiftTests/EvaluatorTest.swift
+++ b/Tests/PklSwiftTests/EvaluatorTest.swift
@@ -347,6 +347,23 @@ final class PklSwiftTests: XCTestCase {
         XCTAssertEqual(output, #"result = "yes pizza"\#n"#)
     }
 
+    func testCustomResourceReaderWithSchemeContainingRegexControlCharacters() async throws {
+        let reader = VirtualResourceReader(
+            scheme: "foo+bar.baz",
+            isGlobbable: false,
+            hasHierarchicalUris: false,
+            read: { _ in [UInt8]("Hello, World!".utf8) },
+            listElements: { _ in [] }
+        )
+        let options = EvaluatorOptions.preconfigured.withResourceReader(reader)
+        XCTAssert(options.allowedResources!.contains(#"\Qfoo+bar.baz:\E"#))
+        let evaluator = try await manager.newEvaluator(options: options)
+        let output = try await evaluator.evaluateOutputText(source: .text("""
+        result = read("foo+bar.baz:quz").text
+        """))
+        XCTAssertEqual(output, #"result = "Hello, World!"\#n"#)
+    }
+
     func testFailedEvaluation() async throws {
         let evaluator = try await manager.newEvaluator(options: EvaluatorOptions.preconfigured)
         do {