<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by Broadridge Transform (tm) - http://www.broadridge.com -->
<!-- Created: Wed Apr 29 22:21:49 UTC 2026 -->
<xs:schema elementFormDefault="qualified" xmlns:ck0000803020="http://www.oberweisfunds.com/20251231" targetNamespace="http://www.oberweisfunds.com/20251231" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:us-types="http://xbrl.us/us-types/2009-01-31" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:dtr="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance">
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xlink:type="simple" xlink:href="ck0000803020-20251231_lab.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef"/>
      <link:linkbaseRef xlink:type="simple" xlink:href="ck0000803020-20251231_pre.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef"/>
      <link:linkbaseRef xlink:type="simple" xlink:href="ck0000803020-20251231_def.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef"/>
    </xs:appinfo>
  </xs:annotation>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/oef/2025" schemaLocation="https://xbrl.sec.gov/oef/2025/oef-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/oef-rr/2025" schemaLocation="https://xbrl.sec.gov/oef/2025/oef-rr-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/fnd-oef/2025" schemaLocation="https://xbrl.sec.gov/fnd/2025/fnd-oef-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:element name="S000010230Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000010230Member"/>
  <xs:element name="S000010231Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000010231Member"/>
  <xs:element name="S000010232Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000010232Member"/>
  <xs:element name="S000015622Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000015622Member"/>
  <xs:element name="S000010233Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000010233Member"/>
  <xs:element name="S000075665Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_S000075665Member"/>
  <xs:element name="C000028299Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000028299Member"/>
  <xs:element name="C000186089Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000186089Member"/>
  <xs:element name="C000028300Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000028300Member"/>
  <xs:element name="C000182411Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000182411Member"/>
  <xs:element name="C000028301Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000028301Member"/>
  <xs:element name="C000186090Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000186090Member"/>
  <xs:element name="C000042583Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000042583Member"/>
  <xs:element name="C000247124Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000247124Member"/>
  <xs:element name="C000028302Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000028302Member"/>
  <xs:element name="C000186091Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000186091Member"/>
  <xs:element name="C000234915Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_C000234915Member"/>
  <xs:element name="SmallsizedCompanyRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_SmallsizedCompanyRiskMember"/>
  <xs:element name="RisksAssociatedWithNonUSCompaniesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_RisksAssociatedWithNonUSCompaniesMember"/>
  <xs:element name="EquitySecuritiesRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_EquitySecuritiesRiskMember"/>
  <xs:element name="MicroCapRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_MicroCapRiskMember"/>
  <xs:element name="EmergingMarketRisksMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_EmergingMarketRisksMember"/>
  <xs:element name="RisksAssociatedWithChineseCompaniesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_RisksAssociatedWithChineseCompaniesMember"/>
  <xs:element name="GovernmentRelationshipsRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_GovernmentRelationshipsRiskMember"/>
  <xs:element name="EquitylinkedCertificatesRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_EquitylinkedCertificatesRiskMember"/>
  <xs:element name="RMBCurrencyRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_RMBCurrencyRiskMember"/>
  <xs:element name="ShanghaiHongKongStockConnectProgramStockConnectRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_ShanghaiHongKongStockConnectProgramStockConnectRiskMember"/>
  <xs:element name="GeographicConcentrationRisksMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_GeographicConcentrationRisksMember"/>
  <xs:element name="CurrencyRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_CurrencyRiskMember"/>
  <xs:element name="FinancialsSectorRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_FinancialsSectorRiskMember"/>
  <xs:element name="NonDiversificationRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_NonDiversificationRiskMember"/>
  <xs:element name="TechnologySectorRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_TechnologySectorRiskMember"/>
  <xs:element name="HealthcareSectorRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_HealthcareSectorRiskMember"/>
  <xs:element name="IndustrialsSectorRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_IndustrialsSectorRiskMember"/>
  <xs:element name="InvestmentStyleRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_InvestmentStyleRiskMember"/>
  <xs:element name="PortfolioTurnoverRiskMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_PortfolioTurnoverRiskMember"/>
  <xs:element name="index_MSCI_EAFE_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_MSCI_EAFE_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
  <xs:element name="index_MSCI_ACWI_Small_Cap_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_MSCI_ACWI_Small_Cap_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
  <xs:element name="index_SP_500_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_SP_500_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
  <xs:element name="index_Russell_Microcap_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_Russell_Microcap_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
  <xs:element name="index_Russell_2000_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_Russell_2000_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
  <xs:element name="index_MSCI_World_EX_US_Small_Cap_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_MSCI_World_EX_US_Small_Cap_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
<!-- [WMV7][kAJNb81oSbCRVJKUXMQpL2kU9TFD2dscs/ThNMPZUUa7uG/omfGtgxCi+7jH3IOOKH/XTAfgspYd4GVTh+NEUWs20vQBDHZuRfRInVRcViz1NPtsaiNy0qxqghuYQL+jYxgVHV/pQmegCKSzrLHiBn9AwGC4QKF36ZIMAerO+/uz8yZKVSG88TEVlkyuqi0PPeJpZPo19UHBd2mOy7jloQOYAmwdm7RDCdJMzZKSaiy0XBrQRPQty3H+8DbfXxhIfwzj6cMMldg34PzxNnjWFgeBOY9+J9EaO1BZ2Zqhh6E50F003YHfhpnVShLf6XXQTlhG9Yqm1hjKirGyFmABzmyYHXA=] CSR-->
  <xs:element name="index_MSCI_China_Net_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="ck0000803020_index_MSCI_China_Net_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember"/>
</xs:schema>
