| | | | | | | | | | | | | | |
| | | | | State or Country |
| | | Name of Subsidiary | | of Incorporation |
| 1 | | Apex Optimisation Limited | | United Kingdom |
| 2 | | Apex Optimisation SRO | | Czech Republic |
| 3 | | Apex Optimisation Technologies B.V. | | Netherlands |
| 4 | | Apex Optimisation (UK) Ltd | | United Kingdom |
| 5 | | Argent & Waugh Limited | | United Kingdom |
| 6 | | Aspen Tech de Mexico, S. de R.L. de C.V. | | Mexico |
| 7 | | Aspen Tech India Private Ltd. | | India |
| 8 | | Aspen Technology (Asia) Inc. | | Delaware |
| 9 | | Aspen Technology Australia Pty. Ltd. | | Australia |
| 10 | | Aspen Technology International, Inc. | | Delaware |
| 11 | | Aspen Technology LLC | | Russia |
| 12 | | Aspen Technology S.A.S. | | Colombia |
| 13 | | Aspen Technology S.L. | | Spain |
| 14 | | Aspen Technology Services Corporation | | Delaware |
| 15 | | AspenTech (Beijing) Ltd. | | PRC |
| 16 | | AspenTech (Shanghai) Ltd. | | PRC |
| 17 | | AspenTech (Thailand) Ltd. | | Thailand |
| 18 | | AspenTech Africa (Pty.) Ltd. | | South Africa |
| 19 | | AspenTech Argentina S.R.L. | | Argentina |
| 20 | | AspenTech Canada Corporation | | Canada |
| 21 | | AspenTech Canada Holdings, LLC | | Delaware |
| 22 | | AspenTech Europe BV | | Netherlands |
| 23 | | AspenTech Europe, SA/NV | | Belgium |
| 24 | | AspenTech Holding Corporation | | Delaware |
| 25 | | AspenTech Japan Co. Ltd. | | Japan |
| 26 | | AspenTech Ltd. | | United Kingdom |
| 27 | | AspenTech Pte. Ltd. | | Singapore |
| 28 | | AspenTech S.r.l. | | Italy |
| 29 | | AspenTech Software Brasil Ltda. | | Brazil |
| 30 | | AspenTech Software Corporation | | Delaware |
| 31 | | AspenTech Solutions Sdn. Bhd. | | Malaysia |
| 32 | | AspenTech Venezuela C.A. | | Venezuela |
| 33 | | Camo Analytics AS | | Norway |
| 34 | | CAMO Smart Software Inc. | | New Jersey |
| 35 | | Camo Software Japan Co Ltd | | Japan |
| 36 | | Hyprotech UK Limited | | United Kingdom |
| 37 | | Mnubo Solutions Inc. d/b/a Mnubo, Inc. | | Canada |
| 38 | | Mtelligence Corporation | | Delaware |
| 39 | | Optiplant Inc. | | Delaware |
| 40 | | Sabisu Ltd. | | United Kingdom |
| 41 | | The Fidelis Group, LLC | | Texas |