Company: TEAM
Filing Date: 2025-10-15
Form Type: DEFA14A
Source: 0001650372-25-000059
Chunk: 0

Company: Atlassian Corp
Filing Date: 2025-10-15
Form: DEFA14A
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549
#### ____________________

#### SCHEDULE 14A

#### Proxy Statement Pursuant to Section 14(a) of the

#### Securities Exchange Act of 1934
<div align='center'>(Amendment No. )</div>

#### ____________________

Filed by the Registrant x Filed by a party other than the Registrant o

CHECK THE APPROPRIATE BOX:

| ¨ |     | Preliminary Proxy Statement                                                     |
| ¨ |     | Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) |
| ¨ |     | Definitive Proxy Statement                                                      |
| x |     | Definitive Additional Materials                                                 |
| ¨ |     | Soliciting Material under §240.14a-12                                           |

#### Atlassian Corporation
<div align='center'>(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)</div>

PAYMENT OF FILING FEE ( CHECK ALL BOXES THAT APPLY ):

| x |     | No fee required                                                                                     |
| ¨ |     | Fee paid previously with preliminary materials                                                      |
| ¨ |     | Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11 |