What is the expected GAAP effective tax rate for EPAM in the first quarter of 2021 
tfolio, we are resuming our full-year guidance for fiscal 2021. While we anticipate growth patterns across the industry verticals to vary throughout the year, we expect our diversified portfolio to drive growth more in line with pre-pandemic levels. At the same time, we will be investing at elevated levels across the business to make certain we have sufficient resources to meet renewed demand.
Additionally, we will increasingly be investing in new geographies to support our long-term growth. One area of focus in 2021 will be the creation of the infrastructure to support a larger and increasingly global EPAM. Starting with our full-year outlook. Revenue growth will be at least 23% on a reported basis and in constant-currency terms will be at least 22% after factoring in a 1% favorable foreign exchange impact.
We expect GAAP income from operations to be in the range of 13.5% to 14.5% and non-GAAP income from operations to be in the range of 16.5% to 17.5%. Our income from operations reflects a higher level of investment in the planned expansion of our capabilities and geographies in 2021. We expect our GAAP effective tax rate to be approximately 12% and our non-GAAP effective tax rate to be approximately 23%. For earnings per share, we expect GAAP diluted EPS to be in the range of $6.65 to $6.86 for the full year and non-GAAP diluted EPS to be in the range of $7.20 to $7.41 for the full year.
We expect weighted average share count of 59 million fully diluted shares outstanding. For Q1 of fiscal year '21, we expect revenues to be in the range of $757 million to $765 million, producing a year-over-year growth rate of approximately 17% at the midpoint of the range. In Q1, we expect the favorable impact of foreign exchange on revenue growth to be approximately 2%. For the first quarter, we expect GAAP income from operations to be in the range of 12.5% to 13.5% and non-GAAP income from operations to be in the range of 16% to 17%.
We expect our GAAP effective tax rate to be approximately 1% and non-GAAP effective tax rate to be approximately 23%. We anticipate our GAAP effective tax rate in the quarter will be impacted by a higher level of excess tax benefits related to the vesting of restricted stock units in connection to our annual compensation cycle. For earnings per share, we expect GAAP diluted EPS to be in the range of $1.66 to $1.74 for the quarter, and non-GAAP diluted EPS to be in the range of $1.62 to $1.70 for the quarter. We expect a weighted average share count of 59 million diluted shares outstanding.
Finally, a few key assumptions that support our GAAP to non-GAAP measurements. Stock compensation expenses is expected to be approximately $86.5 million, with $22.5 million in Q1, $20 million in Q2 and $22 million in the remaining quarters. Amortization of intangibles is expected to be approximately $12.5 million for the year, evenly spread across each quarter. The impact of foreign exchange is expected to be approximately a $5.5 million loss for the year, with $1 million for Q1 and the balance evenly spread across each remaining quarter.
The tax effective non-GAAP adjustments is expected to be around $21.6 million for the year, with $5.1 million for Q1 and Q2 and $5.7 million in each remaining quarter. And finally, we expect excess tax benefits to be around $51.5 million for the full year, with approximately $24.5 million in Q1, $13.5 million in Q2 and $6.8 million in each remaining quarter. In summary, we are pleased with the high-quality results we delivered in fiscal 2020 and are encouraged by what lies ahead in 2021. Operator, let's open the call up for questions.
Questions & Answers:
Operator
[Operator instructions] Our first question comes from Ramsey El-Assal with Barclays. You may proceed with your question.
Ramsey El-Assal -- Barclays -- Analyst
Hi, guys. Thanks for taking my question and congratulations on another strong quarter. Your -- Ark, you mentioned that you're seeing some COVID-related -- you're still seeing a little COVID-related impact for some of your clients. And I think you said potential long
tfolio, we are resuming our full-year guidance for fiscal 2021. While we anticipate growth patterns across the industry verticals to vary throughout the year, we expect our diversified portfolio to drive growth more in line with pre-pandemic levels. At the same time, we will be investing at elevated levels across the business to make certain we have sufficient resources to meet renewed demand.
Additionally, we will increasingly be investing in new geographies to support our long-term growth. One area of focus in 2021 will be the creation of the infrastructure to support a larger and increasingly global EPAM. Starting with our full-year outlook. Revenue growth will be at least 23% on a reported basis and in constant-currency terms will be at least 22% after factoring in a 1% favorable foreign exchange impact.
We expect GAAP income from operations to be in the range of 13.5% to 14.5% and non-GAAP income from operations to be in the range of 16.5% to 17.5%. Our income from operations reflects a higher level of investment in the planned expansion of our capabilities and geographies in 2021. We expect our GAAP effective tax rate to be approximately 12% and our non-GAAP effective tax rate to be approximately 23%. For earnings per share, we expect GAAP diluted EPS to be in the range of $6.65 to $6.86 for the full year and non-GAAP diluted EPS to be in the range of $7.20 to $7.41 for the full year.
We expect weighted average share count of 59 million fully diluted shares outstanding. For Q1 of fiscal year '21, we expect revenues to be in the range of $757 million to $765 million, producing a year-over-year growth rate of approximately 17% at the midpoint of the range. In Q1, we expect the favorable impact of foreign exchange on revenue growth to be approximately 2%. For the first quarter, we expect GAAP income from operations to be in the range of 12.5% to 13.5% and non-GAAP income from operations to be in the range of 16% to 17%.
 We expect our GAAP effective tax rate to be approximately 1% and non-GAAP effective tax rate to be approximately 23%. We anticipate our GAAP effective tax rate in the quarter will be impacted by a higher level of excess tax benefits related to the vesting of restricted stock units in connection to our annual compensation cycle. For earnings per share, we expect GAAP diluted EPS to be in the range of $1.66 to $1.74 for the quarter, and non-GAAP diluted EPS to be in the range of $1.62 to $1.70 for the quarter. We expect a weighted average share count of 59 million diluted shares outstanding.
Finally, a few key assumptions that support our GAAP to non-GAAP measurements. Stock compensation expenses is expected to be approximately $86.5 million, with $22.5 million in Q1, $20 million in Q2 and $22 million in the remaining quarters. Amortization of intangibles is expected to be approximately $12.5 million for the year, evenly spread across each quarter. The impact of foreign exchange is expected to be approximately a $5.5 million loss for the year, with $1 million for Q1 and the balance evenly spread across each remaining quarter.
The tax effective non-GAAP adjustments is expected to be around $21.6 million for the year, with $5.1 million for Q1 and Q2 and $5.7 million in each remaining quarter. And finally, we expect excess tax benefits to be around $51.5 million for the full year, with approximately $24.5 million in Q1, $13.5 million in Q2 and $6.8 million in each remaining quarter. In summary, we are pleased with the high-quality results we delivered in fiscal 2020 and are encouraged by what lies ahead in 2021. Operator, let's open the call up for questions.
Questions & Answers:
Operator
[Operator instructions] Our first question comes from Ramsey El-Assal with Barclays. You may proceed with your question.
Ramsey El-Assal -- Barclays -- Analyst
Hi, guys. Thanks for taking my question and congratulations on another strong quarter. Your -- Ark, you mentioned that you're seeing some COVID-related -- you're still seeing a little COVID-related impact for some of your clients. And I think you said potential long